The relationship between personality, dysfunctional parenting in childhood, and lifetime depression in a sample of employed Japanese adults.

PubMed

Sakado, K; Kuwabara, H; Sato, T; Uehara, T; Sakado, M; Someya, T

2000-10-01

Few studies have explored the relationship between personality, dysfunctional parenting in childhood, and adult depression. Parental rearing styles and personality scores as measured by the Parental Bonding Instrument (PBI) and the Interpersonal Sensitivity Measure (IPSM) were compared in a group of employed Japanese adults with and without a lifetime history of depression. The diagnosis was provided by the Inventory to Diagnose Depression, Lifetime version (IDDL). To estimate the effects of the PBI and the IPSM scores on lifetime depression, a multiple logistic regression analysis was performed. Subjects with lifetime depression were seen to have significantly lower scores on the PBI 'care' and higher scores on the IPSM than the subjects without lifetime depression. Lower levels of maternal care and higher levels of 'interpersonal sensitivity' each independently increased the risk for lifetime depression. The findings of the present study may not be conclusive since the data were retrospectively obtained. Dysfunctional parenting and personality seem to be correlated by lifetime depression, but it is uncertain whether they are independent risk factors

Fatigue lifetime prediction of a reduced-diameter dental implant system: Numerical and experimental study.

PubMed

Duan, Yuanyuan; Gonzalez, Jorge A; Kulkarni, Pratim A; Nagy, William W; Griggs, Jason A

2018-06-16

To validate the fatigue lifetime of a reduced-diameter dental implant system predicted by three-dimensional finite element analysis (FEA) by testing physical implant specimens using an accelerated lifetime testing (ALT) strategy with the apparatus specified by ISO 14801. A commercially-available reduced-diameter titanium dental implant system (Straumann Standard Plus NN) was digitized using a micro-CT scanner. Axial slices were processed using an interactive medical image processing software (Mimics) to create 3D models. FEA analysis was performed in ABAQUS, and fatigue lifetime was predicted using fe-safe ® software. The same implant specimens (n=15) were tested at a frequency of 2Hz on load frames using apparatus specified by ISO 14801 and ALT. Multiple step-stress load profiles with various aggressiveness were used to improve testing efficiency. Fatigue lifetime statistics of physical specimens were estimated in a reliability analysis software (ALTA PRO). Fractured specimens were examined using SEM with fractographic technique to determine the failure mode. FEA predicted lifetime was within the 95% confidence interval of lifetime estimated by experimental results, which suggested that FEA prediction was accurate for this implant system. The highest probability of failure was located at the root of the implant body screw thread adjacent to the simulated bone level, which also agreed with the failure origin in physical specimens. Fatigue lifetime predictions based on finite element modeling could yield similar results in lieu of physical testing, allowing the use of virtual testing in the early stages of future research projects on implant fatigue. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Impact of Perceived Risk and Friend Influence on Alcohol and Marijuana Use Among Students.

PubMed

Merianos, Ashley L; Rosen, Brittany L; Montgomery, LaTrice; Barry, Adam E; Smith, Matthew Lee

2017-12-01

We performed a secondary analysis of Adolescent Health Risk Behavior Survey data ( N = 937), examining associations between lifetime alcohol and marijuana use with intrapersonal (i.e., risk perceptions) and interpersonal (e.g., peer approval and behavior) factors. Multinomial and binary logistic regression analyses contend students reporting lifetime alcohol use-compared to students who had never used alcohol or marijuana-perceived lower alcohol risk ( p < .001), higher friend drinking approval ( p < .001), and greater friend drinking ( p = .003). Using both alcohol and marijuana in one's life was associated with being in public schools ( p = .010), higher grade levels ( p = .001), lower perceived alcohol ( p = .011) and marijuana use risk ( p = .003), higher friend approval of alcohol ( p < .001) and marijuana use ( p < .001), and believed more friends used alcohol ( p < .001). Compared to lifetime alcohol only, perceived friend academic performance decreased the risk of lifetime alcohol and marijuana use ( p = .043). Findings are beneficial to school nurses with students experiencing effects associated with substance use.

Arcjet thruster research and technology

NASA Technical Reports Server (NTRS)

Makel, Darby B.; Cann, Gordon L.

1988-01-01

The design, analysis, and performance testing of an advanced lower power arcjet is described. A high impedance, vortex stabilized 1-kw class arcjet has been studied. A baseline research thruster has been built and endurance and performance tested. This advanced arcjet has demonstrated long lifetime characteristics, but lower than expected performance. Analysis of the specific design has identified modifications which should improve performance and maintain the long life time shown by the arcjet.

Analysis of Nuclear Lifetimes Using the Gamma-ray Induced Doppler Shift Attenuation Method

NASA Astrophysics Data System (ADS)

Crespi, F. C. L.

2018-05-01

Lifetime measurements allow extraction of fundamental information on the nature of the excited states of a nuclear system. Since nuclear lifetimes cover many orders of magnitude, a number of experimental techniques and detection setups have been developed depending on the range of the lifetime of interest. The Gamma-ray Induced Doppler Shift Attenuation (GRIDSA) Method presented here is applied to the measurement of very short lifetimes, in the femtosecond range. It allows determining the nuclear lifetime by measuring the Doppler shift of a gamma ray emitted from the state of interest, in different directions with respect to a coincident preceding gamma ray, populating the same state and inducing a recoil of the nucleus in the target material with velocities of the order of 104-105 m/s. We realized an experiment in order to test the GRIDSA technique for the measurement of fs lifetimes after (n,γ) reactions. The measurement was performed at the Institut Laue-Langevin (ILL) with the 8 Ge-clover detectors of the FIPPS array. Preliminary results are discussed.

Fatigue Analysis of Rotating Parts. A Case Study for a Belt Driven Pulley

NASA Astrophysics Data System (ADS)

Sandu, Ionela; Tabacu, Stefan; Ducu, Catalin

2017-10-01

The present study is focused on the life estimation of a rotating part as a component of an engine assembly namely the pulley of the coolant pump. The goal of the paper is to develop a model, supported by numerical analysis, capable to predict the lifetime of the part. Starting from functional drawing, CAD Model and technical specifications of the part a numerical model was developed. MATLAB code was used to develop a tool to apply the load over the selected area. The numerical analysis was performed in two steps. The first simulation concerned the inertia relief due to rotational motion about the shaft (of the pump). Results from this simulation were saved and the stress - strain state used as initial conditions for the analysis with the load applied. The lifetime of a good part was estimated. A defect was created in order to investigate the influence over the working requirements. It was found that there is little influence with respect to the prescribed lifetime.

Assessing the Lifetime Performance of the Lightning Imaging Sensor (LIS): Implications for the Geostationary Lightning Mapper (GLM)

NASA Technical Reports Server (NTRS)

Buechler, D. E.; Christian, H. J.; Koshak, W. J.; Goodman, S. J.

2011-01-01

The Lightning Imaging Sensor (LIS) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite has been providing observations of total lightning over the Earth s Tropics for 13 years. This study examines the performance of the LIS throughout its time in orbit. Application of the Deep Convective Cloud Technique (DCCT) (Doelling et al., 2004) was performed on the LIS background pixels to assess the stability of the LIS instrument. The DCCT analysis indicates that the maximum deviation of the monthly mean radiance is within 2% of the overall mean, indicating stable performance over the period. In addition, an examination of the number of flashes detected over time similarly shows no significant trend (after adjusting for the orbit boost that occurred in August 2001). These and other results indicate that there has been no discernible change in LIS performance throughout its lifetime. A similar approach will used for monitoring the performance of the Geostationary Lightning Mapper (GLM) onboard the next generation Geostationary Operational Environmental Satellite-R (GOES-R). Since GLM is based on LIS design heritage, the LIS results indicate that GLM may also experience stable performance over its lifetime.

Outgas analysis of mechanical cryocoolers for long lifetime

NASA Astrophysics Data System (ADS)

Sato, Yoichi; Shinozaki, Keisuke; Sawada, Kenichiro; Sugita, Hiroyuki; Mitsuda, Kazuhisa; Yamasaki, Noriko Y.; Nakagawa, Takao; Tsunematsu, Shoji; Otsuka, Kiyomi; Kanao, Kenichi; Yoshida, Seiji; Narasaki, Katsuhiro

2017-12-01

Mechanical cryocoolers for space applications are required to have high reliability to achieve long-term operation in orbit. ASTRO-H (Hitomi), the 6th Japanese X-ray astronomy mission, has a major scientific instrument onboard-the Soft X-ray Spectrometer (SXS) with several 20K-class two-stage Stirling (2ST) coolers and a 4K-class Joule Thomson (JT) cooler, which must operate for 3 years to ensure the lifetime of liquid helium as a cryogen for cooling of its detectors [1,2]. Other astronomical missions such as SPICA [3,4], LiteBIRD [5], and Athena [6] also have top requirements for these mechanical cryocoolers, including a 1K-class JT cooler to be operated for more than 3-5 years with no cryogen system. The reliability and lifetime of mechanical cryocoolers are generally understood to depend on (1) mechanical wear of the piston seal and valve seal, and (2) He working gas contaminated by impurity outgases, mainly H2O and CO2 released from the materials in the components of the cryocoolers. The second factor could be critical relative to causing blockage in the JT heat exchanger plumbing and the JT orifice or resulting in blockage in the Stirling regenerator and thereby degrading its performance. Thus, reducing the potential for outgassing in the cryocooler design and fabrication process, and predicting the total amount of outgases in the cryocooler are very important to ensure cryocooler lifetime and cooling performance in orbit. This paper investigates the outgas analysis of the 2ST and the 1K/4K-JT coolers for achieving a long lifetime. First, gas analysis was conducted for the materials and components of the mechanical cryocoolers, focusing on non-metallic materials as impurity gas sources. Then gas analysis of the mechanical wear effect of the piston seal materials and linear ball bearings was investigated. Finally, outgassing from a fully assembled cryocooler was measured to evaluate whether the outgas reduction process works properly to meet the requirement levels.

Continued Analysis of the NIST Neutron Lifetime Measurement Using Ultracold Neutrons

NASA Astrophysics Data System (ADS)

Huffer, Craig; Huffman, P. R.; Schelhammer, K. W.; Dewey, M. S.; Huber, M. G.; Hughes, P. P.; Mumm, H. P.; Thompson, A. K.; Coakley, K.; Yue, A. T.; O'Shaughnessy, C. M.; Yang, L.

2013-10-01

The neutron lifetime is an important parameter for constraining the Standard Model and providing input for Big Bang Nucleosynthesis. The current disagreement in the most recent generation of lifetime experiments suggests unknown or underestimated systematics and motivates the need for alternative measurement methods as well as additional investigations into potential systematics. Our measurement was performed using magnetically trapped Ultracold Neutrons in a 3.1 T Ioffe type trap configuration. The decay rate of the neutron population is recorded in real time by monitoring visible light resulting from beta decay. Data collected in late 2010 and early 2011 is being analyzed and systematic effects are being investigated. An overview of our current work on the analysis, Monte Carlo simulations, and systematic effects will be provided. This work was supported by the NSF and NIST.

Cost-Utility Analysis of Bariatric Surgery in Italy: Results of Decision-Analytic Modelling

PubMed Central

Lucchese, Marcello; Borisenko, Oleg; Mantovani, Lorenzo Giovanni; Cortesi, Paolo Angelo; Cesana, Giancarlo; Adam, Daniel; Burdukova, Elisabeth; Lukyanov, Vasily; Di Lorenzo, Nicola

2017-01-01

Objective To evaluate the cost-effectiveness of bariatric surgery in Italy from a third-party payer perspective over a medium-term (10 years) and a long-term (lifetime) horizon. Methods A state-transition Markov model was developed, in which patients may experience surgery, post-surgery complications, diabetes mellitus type 2, cardiovascular diseases or die. Transition probabilities, costs, and utilities were obtained from the Italian and international literature. Three types of surgeries were considered: gastric bypass, sleeve gastrectomy, and adjustable gastric banding. A base-case analysis was performed for the population, the characteristics of which were obtained from surgery candidates in Italy. Results In the base-case analysis, over 10 years, bariatric surgery led to cost increment of EUR 2,661 and generated additional 1.1 quality-adjusted life years (QALYs). Over a lifetime, surgery led to savings of EUR 8,649, additional 0.5 life years and 3.2 QALYs. Bariatric surgery was cost-effective at 10 years with an incremental cost-effectiveness ratio of EUR 2,412/QALY and dominant over conservative management over a lifetime. Conclusion In a comprehensive decision analytic model, a current mix of surgical methods for bariatric surgery was cost-effective at 10 years and cost-saving over the lifetime of the Italian patient cohort considered in this analysis. PMID:28601866

Ultrafast Method for the Analysis of Fluorescence Lifetime Imaging Microscopy Data Based on the Laguerre Expansion Technique

PubMed Central

Jo, Javier A.; Fang, Qiyin; Marcu, Laura

2007-01-01

We report a new deconvolution method for fluorescence lifetime imaging microscopy (FLIM) based on the Laguerre expansion technique. The performance of this method was tested on synthetic and real FLIM images. The following interesting properties of this technique were demonstrated. 1) The fluorescence intensity decay can be estimated simultaneously for all pixels, without a priori assumption of the decay functional form. 2) The computation speed is extremely fast, performing at least two orders of magnitude faster than current algorithms. 3) The estimated maps of Laguerre expansion coefficients provide a new domain for representing FLIM information. 4) The number of images required for the analysis is relatively small, allowing reduction of the acquisition time. These findings indicate that the developed Laguerre expansion technique for FLIM analysis represents a robust and extremely fast deconvolution method that enables practical applications of FLIM in medicine, biology, biochemistry, and chemistry. PMID:19444338

Retrospective lifetime dietary patterns predict cognitive performance in community-dwelling older Australians.

PubMed

Hosking, Diane E; Nettelbeck, Ted; Wilson, Carlene; Danthiir, Vanessa

2014-07-28

Dietary intake is a modifiable exposure that may have an impact on cognitive outcomes in older age. The long-term aetiology of cognitive decline and dementia, however, suggests that the relevance of dietary intake extends across the lifetime. In the present study, we tested whether retrospective dietary patterns from the life periods of childhood, early adulthood, adulthood and middle age predicted cognitive performance in a cognitively healthy sample of 352 older Australian adults >65 years. Participants completed the Lifetime Diet Questionnaire and a battery of cognitive tests designed to comprehensively assess multiple cognitive domains. In separate regression models, lifetime dietary patterns were the predictors of cognitive factor scores representing ten constructs derived by confirmatory factor analysis of the cognitive test battery. All regression models were progressively adjusted for the potential confounders of current diet, age, sex, years of education, English as native language, smoking history, income level, apoE ɛ4 status, physical activity, other past dietary patterns and health-related variables. In the adjusted models, lifetime dietary patterns predicted cognitive performance in this sample of older adults. In models additionally adjusted for intake from the other life periods and mechanistic health-related variables, dietary patterns from the childhood period alone reached significance. Higher consumption of the 'coffee and high-sugar, high-fat extras' pattern predicted poorer performance on simple/choice reaction time, working memory, retrieval fluency, short-term memory and reasoning. The 'vegetable and non-processed' pattern negatively predicted simple/choice reaction time, and the 'traditional Australian' pattern positively predicted perceptual speed and retrieval fluency. Identifying early-life dietary antecedents of older-age cognitive performance contributes to formulating strategies for delaying or preventing cognitive decline.

Measuring upconversion nanoparticles photoluminescence lifetime with FastFLIM and phasor plots

NASA Astrophysics Data System (ADS)

Sun, Yuansheng; Lee, Hsien-Ming; Qiu, Hailin; Liao, Shih-Chu Jeff; Coskun, Ulas; Barbieri, Beniamino

2018-02-01

Photon upconversion is a nonlinear process in which the sequential of absorption of two or more photons leads to the anti-stoke emission. Different than the conventional multiphoton excitation process, upconversion can be efficiently performed at low excitation densities. Recent developments in lanthanide-doped upconversion nanoparticles (UCNPs) have led to a diversity of applications, including detecting and sensing of biomolecules, imaging of live cells, tissues and animals, cancer diagnostic and therapy, etc. Measuring the upconversion lifetime provides a new dimension of its imaging and opens a new window for its applications. Due to the long metastable intermediate excited state, UCNP typically has a long excited state lifetime ranging from sub-microseconds to milliseconds. Here, we present a novel development using the FastFLIM technique to measure UCNP lifetime by laser scanning confocal microscopy. FastFLIM is capable of measuring lifetime from 100 ps to 100 ms and features the high data collection efficiency (up to 140-million counts per second). Other than the traditional nonlinear least-square fitting analysis, the raw data acquired by FastFLIM can be directly processed by the model-free phasor plots approach for instant and unbiased lifetime results, providing the ideal routine for the UCNP photoluminescence lifetime microscopy imaging.

Correlation of the superconducting transition to oxygen stoichiometry in single-crystal Ba1-xKxBiO3-y

NASA Astrophysics Data System (ADS)

Mosley, W. D.; Dykes, J. W.; Klavins, P.; Shelton, R. N.; Sterne, P. A.; Howell, R. H.

1993-07-01

Temperature-dependent positron-lifetime experiments have been performed from room temperature to 15 K on single crystals of the oxide superconductor Ba1-xKxBiO3-y. Results indicate that the filling of oxygen vacancies has a marked impact on the superconducting properties of this system. Cation defect concentrations were below the detectable limit of positron-annihilation-analysis techniques in this material, which is in sharp contrast to identical studies on polycrystalline samples. We find that the positron lifetime in these electrochemically deposited single crystals is determined by the oxygen stoichiometry of the lattice, but there is no experimental signature of strong positron localization. By performing a subsequent oxygen anneal on the crystals, the superconducting transition is sharpened and the onset is raised. The observed change in positron lifetime associated with this annealing procedure is in quantitative agreement with theory.

Fluorescence lifetime imaging system with nm-resolution and single-molecule sensitivity

NASA Astrophysics Data System (ADS)

Wahl, Michael; Rahn, Hans-Juergen; Ortmann, Uwe; Erdmann, Rainer; Boehmer, Martin; Enderlein, Joerg

2002-03-01

Fluorescence lifetime measurement of organic fluorophores is a powerful tool for distinguishing molecules of interest from background or other species. This is of interest in sensitive analysis and Single Molecule Detection (SMD). A demand in many applications is to provide 2-D imaging together with lifetime information. The method of choice is then Time-Correlated Single Photon Counting (TCSPC). We have devloped a compact system on a single PC board that can perform TCSPC at high throughput, while synchronously driving a piezo scanner holding the immobilized sample. The system allows count rates up to 3 MHz and a resolution down to 30 ps. An overall Instrument Response Function down to 300ps is achieved with inexpensive detectors and diode lasers. The board is designed for the PCI bus, permitting high throughput without loss of counts. It is reconfigurable to operate in different modes. The Time-Tagged Time-Resolved (TTTR) mode permits the recording of all photon events with a real-time tag allowing data analysis with unlimited flexibility. We use the Time-Tag clock for an external piezo scanner that moves the sample. As the clock source is common for scanning and tagging, the individual photons can be matched to pixels. Demonstrating the capablities of the system we studied single molecule solutions. Lifetime imaging can be performed at high resolution with as few as 100 photons per pixel.

Lifetime prevalence of suicidal ideation among men who have sex with men: a meta-analysis.

PubMed

Luo, Zhenzhou; Feng, Tiejian; Fu, Hanlin; Yang, Tubao

2017-12-21

Suicide is a leading cause of death among men who have sex with men (MSM) and suicidal ideation may put individuals at higher risk of suicide. A great disparity of lifetime prevalence of suicidal ideation among MSM was observed across studies, indicating the importance of a reliable estimation of the pooled lifetime prevalence. However, the only one published meta-analysis estimating the pooled lifetime prevalence of suicidal ideation among MSM was conducted in 2008 with only 2 eligible studies. Subsequently, there was a rapid increase of publications about lifetime suicidal ideation among MSM, suggesting that an update on the pooled lifetime prevalence of suicidal ideation among MSM was necessary. Therefore, this study aimed to update the estimation of the pooled lifetime prevalence of suicidal ideation among MSM. Electronic databases of PubMed, CINAHL, Scopus (social science), Embase and PsycInfo were searched until September 2017 to identify relevant studies. Cross-sectional studies exploring the lifetime prevalence of suicidal ideation among MSM were enrolled. Heterogeneity was evaluated using the Cochran Q test and quantified using the I 2 statistic. The possibility of publication bias was assessed using both Begg's rank test and Egger's linear test, and an Egger's funnel plot for asymmetry was presented. Subgroup analyses were performed according to the geographic area, sample source and HIV status. Nineteen studies with a total of 26,667 MSM were included, of which 9374 were identified with suicidal ideation. A high degree of heterogeneity (P ≤ 0.001, I 2 =99.2%) was observed among the eligible studies, with the reported prevalence ranging from 13.18 to 55.80%. The pooled lifetime prevalence of suicidal ideation among MSM by a random effects model was 34.97% (95% confidence interval: 28.35%-41.90%). Both the Begg's rank test and Egger's linear test indicated low possibility of publication bias. Subgroup analyses showed that the lifetime prevalence of suicidal ideation among MSM differed significantly by geographic area, sample source and HIV status (P < 0.05). The high pooled lifetime prevalence of suicidal ideation among MSM found in this meta-analysis significantly underscores the importance of early assessment of suicidal ideation among MSM, as well as the need for strengthening the psychological interventions.

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic waste repository: 1. Theory, illustrations, and implications

NASA Astrophysics Data System (ADS)

Cornaton, F. J.; Park, Y.-J.; Normani, S. D.; Sudicky, E. A.; Sykes, J. F.

2008-04-01

Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, if radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from a repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time that radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport adjoint equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. The risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The utility of the method is illustrated by means of analytical and numerical examples, which focus on the effect of fracture networks on the uncertainty of evaluated lifetime expectancy.

The failure analysis and lifetime prediction for the solder joint of the magnetic head

NASA Astrophysics Data System (ADS)

Xiao, Xianghui; Peng, Minfang; Cardoso, Jaime S.; Tang, Rongjun; Zhou, YingLiang

2015-02-01

Micro-solder joint (MSJ) lifetime prediction methodology and failure analysis (FA) are to assess reliability by fatigue model with a series of theoretical calculations, numerical simulation and experimental method. Due to shortened time of solder joints on high-temperature, high-frequency sampling error that is not allowed in productions may exist in various models, including round-off error. Combining intermetallic compound (IMC) growth theory and the FA technology for the magnetic head in actual production, this thesis puts forward a new growth model to predict life expectancy for solder joint of the magnetic head. And the impact of IMC, generating from interface reaction between slider (magnetic head, usually be called slider) and bonding pad, on mechanical performance during aging process is analyzed in it. By further researching on FA of solder ball bonding, thesis chooses AuSn4 growth model that affects least to solder joint mechanical property to indicate that the IMC methodology is suitable to forecast the solder lifetime. And the diffusion constant under work condition 60 °C is 0.015354; the solder lifetime t is 14.46 years.

Summary of EOS flight dynamics analysis

NASA Technical Reports Server (NTRS)

Newman, Lauri Kraft; Folta, David C.

1995-01-01

From a flight dynamics perspective, the Earth Observing System (EOS) spacecraft present a number of challenges to mission designers. The Flight Dynamics Support Branch of NASA GSFC has examined a number of these challenges, including managing the EOS constellation, disposing of the spacecraft at the end-of-life (EOL), and achieving the appropriate mission orbit given launch vehicle and ascent propulsion constraints. The EOS program consists of a number of spacecraft including EOS-AM, an ascending node spacecraft, EOS-PM, a descending node spacecraft, the EOS Chemistry mission (EOS-CHEM), the EOS Altimetry Laser (EOS-LALT), and the EOS-Altimetry Radar (EOS-RALT). The orbit characteristics of these missions are presented. In order to assure that downlinking data from each spacecraft will be possible without interference between any two spacecraft, a careful examination of the relationships between spacecraft and how to maintain the spacecraft in a configuration which would minimize these communications problems must be made. The FDSB has performed various analyses to determine whether the spacecraft will be in a position to interfere with each other, how the orbit dynamics will change the relative positioning of the spacecraft over their lifetimes, and how maintenance maneuvers could be performed, if needed, to minimize communications problems. Prompted by an activity at NASA HQ to set guidelines for spacecraft regarding their end-of-life dispositions, much analysis has also been performed to determine the spacecraft lifetime of EOS-AM1 under various conditions, and to make suggestions regarding the spacecraft disposal. In performing this analysis, some general trends have been observed in lifetime calculations. The paper will present the EOS-AM1 lifetime results, comment on general reentry conclusions, and discuss how these analyses reflect on the HQ NMI. Placing the EOS spacecraft into their respective mission orbits involves some intricate maneuver planning to assure that all mission orbit requirements are met, given the initial conditions supplied by the launch vehicle at injection. The FDSB has developed an ascent scenario to meet the mission requirements. This paper presents results of the ascent analysis.

Performance capabilities of the 8-cm mercury ion thruster

NASA Technical Reports Server (NTRS)

Mantenieks, M. A.

1981-01-01

A preliminary characterization of the performance capabilities of the 8-cm thruster in order to initiate an evaluation of its application to LSS propulsion requirements is presented. With minor thruster modifications, the thrust was increased by about a factor of four while the discharge voltage was reduced from 39 to 22 volts. The thruster was operated over a range of specific impulse of 1950 to 3040 seconds and a maximum total efficiency of about 54 percent was attained. Preliminary analysis of component lifetimes, as determined by temperature and spectroscopic line intensity measurements, indicated acceptable thruster lifetimes are anticipated at the high power level operation.

Monolayer dispersion of CoO on Al2O3 probed by positronium atom

NASA Astrophysics Data System (ADS)

Liu, Z. W.; Zhang, H. J.; Chen, Z. Q.

2014-02-01

CoO/Al2O3 catalysts were prepared by wet impregnation method with CoO contents ranging from 0 wt% to 24 wt%. X-ray diffraction and X-ray photoelectron spectroscopy measurements suggest formation of CoO after calcined in N2. Quantitative X-ray diffraction analysis indicates monolayer dispersion capacity of CoO in CoO/Al2O3 catalysts to be about 3 wt%. Positron annihilation lifetime and coincidence Doppler broadening measurements were performed to study the dispersion state of CoO on Al2O3. The positron lifetime measurements reveal two long lifetime components τ3 and τ4, which correspond to ortho-positronium annihilation lifetime in microvoids and large pores, respectively. It was found that the positronium atom is very sensitive to the dispersion state of CoO on Al2O3. The presence of CoO significantly decreases both the lifetime and the intensity of τ4. Detailed analysis of the coincidence Doppler broadening measurements suggests that with the CoO content lower than the monolayer dispersion, spin conversion reaction of positronium is induced by CoO. When the cobalt content is higher than the monolayer dispersion capacity, inhibition of positronium formation becomes the dominate effect.

Known Good Substrates Year 1

DTIC Science & Technology

2007-12-05

yield record setting carrier lifetime values and very low concentrations of point defects. Epiwafers delivered for fabrication of RF static induction ...boules and on improved furnace uniformity (adding rotation, etc.). Pareto analysis was performed on wafer yield loss at the start of every quarter...100mm PVT process. Work focused on modeling the process for longer (50 mm) boules and on improved furnace uniformity. Pareto analysis was performed

Cost-Utility Analysis of Bariatric Surgery in Italy: Results of Decision-Analytic Modelling.

PubMed

Lucchese, Marcello; Borisenko, Oleg; Mantovani, Lorenzo Giovanni; Cortesi, Paolo Angelo; Cesana, Giancarlo; Adam, Daniel; Burdukova, Elisabeth; Lukyanov, Vasily; Di Lorenzo, Nicola

2017-01-01

To evaluate the cost-effectiveness of bariatric surgery in Italy from a third-party payer perspective over a medium-term (10 years) and a long-term (lifetime) horizon. A state-transition Markov model was developed, in which patients may experience surgery, post-surgery complications, diabetes mellitus type 2, cardiovascular diseases or die. Transition probabilities, costs, and utilities were obtained from the Italian and international literature. Three types of surgeries were considered: gastric bypass, sleeve gastrectomy, and adjustable gastric banding. A base-case analysis was performed for the population, the characteristics of which were obtained from surgery candidates in Italy. In the base-case analysis, over 10 years, bariatric surgery led to cost increment of EUR 2,661 and generated additional 1.1 quality-adjusted life years (QALYs). Over a lifetime, surgery led to savings of EUR 8,649, additional 0.5 life years and 3.2 QALYs. Bariatric surgery was cost-effective at 10 years with an incremental cost-effectiveness ratio of EUR 2,412/QALY and dominant over conservative management over a lifetime. In a comprehensive decision analytic model, a current mix of surgical methods for bariatric surgery was cost-effective at 10 years and cost-saving over the lifetime of the Italian patient cohort considered in this analysis. © 2017 The Author(s) Published by S. Karger GmbH, Freiburg.

Fluid-structure interaction analysis and lifetime estimation of a natural gas pipeline centrifugal compressor under near-choke and near-surge conditions

NASA Astrophysics Data System (ADS)

Ju, Yaping; Liu, Hui; Yao, Ziyun; Xing, Peng; Zhang, Chuhua

2015-11-01

Up to present, there have been no studies concerning the application of fluid-structure interaction (FSI) analysis to the lifetime estimation of multi-stage centrifugal compressors under dangerous unsteady aerodynamic excitations. In this paper, computational fluid dynamics (CFD) simulations of a three-stage natural gas pipeline centrifugal compressor are performed under near-choke and near-surge conditions, and the unsteady aerodynamic pressure acting on impeller blades are obtained. Then computational structural dynamics (CSD) analysis is conducted through a one-way coupling FSI model to predict alternating stresses in impeller blades. Finally, the compressor lifetime is estimated using the nominal stress approach. The FSI results show that the impellers of latter stages suffer larger fluctuation stresses but smaller mean stresses than those at preceding stages under near-choke and near-surge conditions. The most dangerous position in the compressor is found to be located near the leading edge of the last-stage impeller blade. Compressor lifetime estimation shows that the investigated compressor can run up to 102.7 h under the near-choke condition and 200.2 h under the near-surge condition. This study is expected to provide a scientific guidance for the operation safety of natural gas pipeline centrifugal compressors.

On the uncertainty in single molecule fluorescent lifetime and energy emission measurements

NASA Technical Reports Server (NTRS)

Brown, Emery N.; Zhang, Zhenhua; Mccollom, Alex D.

1995-01-01

Time-correlated single photon counting has recently been combined with mode-locked picosecond pulsed excitation to measure the fluorescent lifetimes and energy emissions of single molecules in a flow stream. Maximum likelihood (ML) and least square methods agree and are optimal when the number of detected photons is large however, in single molecule fluorescence experiments the number of detected photons can be less than 20, 67% of those can be noise and the detection time is restricted to 10 nanoseconds. Under the assumption that the photon signal and background noise are two independent inhomogeneous poisson processes, we derive the exact joint arrival time probably density of the photons collected in a single counting experiment performed in the presence of background noise. The model obviates the need to bin experimental data for analysis, and makes it possible to analyze formally the effect of background noise on the photon detection experiment using both ML or Bayesian methods. For both methods we derive the joint and marginal probability densities of the fluorescent lifetime and fluorescent emission. the ML and Bayesian methods are compared in an analysis of simulated single molecule fluorescence experiments of Rhodamine 110 using different combinations of expected background nose and expected fluorescence emission. While both the ML or Bayesian procedures perform well for analyzing fluorescence emissions, the Bayesian methods provide more realistic measures of uncertainty in the fluorescent lifetimes. The Bayesian methods would be especially useful for measuring uncertainty in fluorescent lifetime estimates in current single molecule flow stream experiments where the expected fluorescence emission is low. Both the ML and Bayesian algorithms can be automated for applications in molecular biology.

On the Uncertainty in Single Molecule Fluorescent Lifetime and Energy Emission Measurements

NASA Technical Reports Server (NTRS)

Brown, Emery N.; Zhang, Zhenhua; McCollom, Alex D.

1996-01-01

Time-correlated single photon counting has recently been combined with mode-locked picosecond pulsed excitation to measure the fluorescent lifetimes and energy emissions of single molecules in a flow stream. Maximum likelihood (ML) and least squares methods agree and are optimal when the number of detected photons is large, however, in single molecule fluorescence experiments the number of detected photons can be less than 20, 67 percent of those can be noise, and the detection time is restricted to 10 nanoseconds. Under the assumption that the photon signal and background noise are two independent inhomogeneous Poisson processes, we derive the exact joint arrival time probability density of the photons collected in a single counting experiment performed in the presence of background noise. The model obviates the need to bin experimental data for analysis, and makes it possible to analyze formally the effect of background noise on the photon detection experiment using both ML or Bayesian methods. For both methods we derive the joint and marginal probability densities of the fluorescent lifetime and fluorescent emission. The ML and Bayesian methods are compared in an analysis of simulated single molecule fluorescence experiments of Rhodamine 110 using different combinations of expected background noise and expected fluorescence emission. While both the ML or Bayesian procedures perform well for analyzing fluorescence emissions, the Bayesian methods provide more realistic measures of uncertainty in the fluorescent lifetimes. The Bayesian methods would be especially useful for measuring uncertainty in fluorescent lifetime estimates in current single molecule flow stream experiments where the expected fluorescence emission is low. Both the ML and Bayesian algorithms can be automated for applications in molecular biology.

Recent Advances in Fluorescence Lifetime Analytical Microsystems: Contact Optics and CMOS Time-Resolved Electronics.

PubMed

Wei, Liping; Yan, Wenrong; Ho, Derek

2017-12-04

Fluorescence spectroscopy has become a prominent research tool with wide applications in medical diagnostics and bio-imaging. However, the realization of combined high-performance, portable, and low-cost spectroscopic sensors still remains a challenge, which has limited the technique to the laboratories. A fluorescence lifetime measurement seeks to obtain the characteristic lifetime from the fluorescence decay profile. Time-correlated single photon counting (TCSPC) and time-gated techniques are two key variations of time-resolved measurements. However, commercial time-resolved analysis systems typically contain complex optics and discrete electronic components, which lead to bulkiness and a high cost. These two limitations can be significantly mitigated using contact sensing and complementary metal-oxide-semiconductor (CMOS) implementation. Contact sensing simplifies the optics, whereas CMOS technology enables on-chip, arrayed detection and signal processing, significantly reducing size and power consumption. This paper examines recent advances in contact sensing and CMOS time-resolved circuits for the realization of fully integrated fluorescence lifetime measurement microsystems. The high level of performance from recently reported prototypes suggests that the CMOS-based contact sensing microsystems are emerging as sound technologies for application-specific, low-cost, and portable time-resolved diagnostic devices.

Recent Advances in Fluorescence Lifetime Analytical Microsystems: Contact Optics and CMOS Time-Resolved Electronics

PubMed Central

Yan, Wenrong; Ho, Derek

2017-01-01

Fluorescence spectroscopy has become a prominent research tool with wide applications in medical diagnostics and bio-imaging. However, the realization of combined high-performance, portable, and low-cost spectroscopic sensors still remains a challenge, which has limited the technique to the laboratories. A fluorescence lifetime measurement seeks to obtain the characteristic lifetime from the fluorescence decay profile. Time-correlated single photon counting (TCSPC) and time-gated techniques are two key variations of time-resolved measurements. However, commercial time-resolved analysis systems typically contain complex optics and discrete electronic components, which lead to bulkiness and a high cost. These two limitations can be significantly mitigated using contact sensing and complementary metal-oxide-semiconductor (CMOS) implementation. Contact sensing simplifies the optics, whereas CMOS technology enables on-chip, arrayed detection and signal processing, significantly reducing size and power consumption. This paper examines recent advances in contact sensing and CMOS time-resolved circuits for the realization of fully integrated fluorescence lifetime measurement microsystems. The high level of performance from recently reported prototypes suggests that the CMOS-based contact sensing microsystems are emerging as sound technologies for application-specific, low-cost, and portable time-resolved diagnostic devices. PMID:29207568

One method for life time estimation of a bucket wheel machine for coal moving

NASA Astrophysics Data System (ADS)

Vîlceanu, Fl; Iancu, C.

2016-08-01

Rehabilitation of outdated equipment with lifetime expired, or in the ultimate life period, together with high cost investments for their replacement, makes rational the efforts made to extend their life. Rehabilitation involves checking operational safety based on relevant expertise of metal structures supporting effective resistance and assessing the residual lifetime. The bucket wheel machine for coal constitute basic machine within deposits of coal of power plants. The estimate of remaining life can be done by checking the loading on the most stressed subassembly by Finite Element Analysis on a welding detail. The paper presents step-by-step the method of calculus applied in order to establishing the residual lifetime of a bucket wheel machine for coal moving using non-destructive methods of study (fatigue cracking analysis + FEA). In order to establish the actual state of machine and areas subject to study, was done FEA of this mining equipment, performed on the geometric model of mechanical analyzed structures, with powerful CAD/FEA programs. By applying the method it can be calculated residual lifetime, by extending the results from the most stressed area of the equipment to the entire machine, and thus saving time and money from expensive replacements.

The inverse power law model for the lifetime of a mylar-polyurethane laminated dc hv insulating structure

NASA Astrophysics Data System (ADS)

Kalkanis, G.; Rosso, E.

1989-09-01

Results of an accelerated test on the lifetime of a mylar-polyurethane laminated dc high voltage insulating structure are reported. This structure consists of mylar ribbons placed side by side in a number of layers, staggered and glued together with a polyurethane adhesive. The lifetime until breakdown as a function of extremely high values of voltage stress is measured and represented by a mathematical model, the inverse power law model with a 2-parameter Weibull lifetime distribution. The statistical treatment of the data — either by graphical or by analytical methods — allowed us to estimate the lifetime distribution and confidence bounds for any required normal voltage stress. The laminated structure under consideration is, according to the analysis, a very reliable dc hv insulating material, with a very good life performance according to the inverse power law model, and with an exponent of voltage stress equal to 6. A large insulator of cylindrical shape with this kind of laminated structure can be constructed by winding helically a mylar ribbon in a number of layers.

Stability and lifetime testing of photomultiplier detectors for the Earth observing system SOLSTICE program

NASA Astrophysics Data System (ADS)

Hadler, Joshua A.; van de Kop, Toni; Drake, Virginia A.; McClintock, William E.; Murphy, John; Rodgers, Paul

1998-10-01

The primary objective of the Earth Observing System (EOS) Solar Stellar Irradiance Comparison Experiment (SOLSTICE) is to accurately measure the absolute value of the solar UV irradiance at the top of the earth's atmosphere for a minimum mission lifetime of 5 years. To meet this objective, SOLSTICE employs a unique design to determine changes in instrument performance by routinely observing a series of early-type stars and comparing the irradiances directly with the solar value. Although the comparison techniques allows us to track instrument performance, the success of the SOLSTICE experiment depends upon photomultiplier detectors which have graceful degradation properties. Therefore, we have established a laboratory program to evaluate the characteristics of photomultiplier tubes which are exposed to long term fluxes similar to those we expected to encounter in flight. Three types of Hamamatsu photomultiplier tubes were tested as candidates for use in the EOS-SOLSTICE project. The results of these studies: pulse height distribution; quantum efficiency; surface maps,; and lifetime analysis are presented in this paper.

Sns Moderator Poison Design and Experiment Validation of the Moderator Performance

NASA Astrophysics Data System (ADS)

Lu, W.; Iverson, E. B.; Ferguson, P. D.; Crabtree, J. A.; Gallmeier, F. X.; Remec, I.; Baxter, D. V.; Lavelle, C. M.

2009-08-01

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory reached 180 kW in August 2007, becoming the brightest pulsed neutron source in the world. At its full power of 1.4 MW, SNS will have thermal neutron fluxes approximately an order of magnitude greater than any existing pulsed spallation source. It thus brings a serious challenge to the lifetime of the moderator poison sheets. The SNS moderators are integrated with the inner reflector plug (IRP) at a cost of $2 million a piece. A replacement of the IRP presents a significant drawback to the facility due to the activation and the operation cost. Although there are many factors limiting the lifetime of the IRP, such as radiation damage to the structural material and helium production in beryllium, the limiting factor is the lifetime of the moderator poison sheets. The current operating target system of SNS was built with thick Gd poison sheets at a projected lifetime of 3 years. A recent design based on the MCNPX calculation proposed to replace the Gd poison sheets with even thicker Cd poison sheets, aiming to extend the poison sheet lifetime from 3 to 4 years accompanied by an approximate 5% gain of the moderator performance. An experiment was carried out to verify the calculated moderator performance at the Low Energy Neutron Source (LENS), Indiana University, where the spectra of two polyethylene moderators were measured. The moderators are Cd-decoupled and are poisoned with 0.8 mm Gd and 1.2 mm Cd, respectively. The preliminary analysis of the experiment data shows that the characteristics of the measured spectra of the Gd- and Cd-poisoned moderators agree well with what the calculation predicted. A better moderator performance is observed in the Cd-poisoned moderator. The measured ratio of Cd over Gd on the moderator performance is in a reasonable agreement with the calculation. Further investigation is underway for a better understanding of the difference between the experiment and the calculation.

Do recognizable lifetime eating disorder phenotypes naturally occur in a culturally asian population? A combined latent profile and taxometric approach.

PubMed

Thomas, Jennifer J; Eddy, Kamryn T; Ruscio, John; Ng, King Lam; Casale, Kristen E; Becker, Anne E; Lee, Sing

2015-05-01

We examined whether empirically derived eating disorder (ED) categories in Hong Kong Chinese patients (N = 454) would be consistent with recognizable lifetime ED phenotypes derived from latent structure models of European and American samples. We performed latent profile analysis (LPA) using indicator variables from data collected during routine assessment, and then applied taxometric analysis to determine whether latent classes were qualitatively versus quantitatively distinct. Latent profile analysis identified four classes: (i) binge/purge (47%); (ii) non-fat-phobic low-weight (34%); (iii) fat-phobic low-weight (12%); and (iv) overweight disordered eating (6%). Taxometric analysis identified qualitative (categorical) distinctions between the binge/purge and non-fat-phobic low-weight classes, and also between the fat-phobic and non-fat-phobic low-weight classes. Distinctions between the fat-phobic low-weight and binge/purge classes were indeterminate. Empirically derived categories in Hong Kong showed recognizable correspondence with recognizable lifetime ED phenotypes. Although taxometric findings support two distinct classes of low weight EDs, LPA findings also support heterogeneity among non-fat-phobic individuals. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

Positron lifetime studies of defect structures in Ba(1-x)K(x)BiO3

NASA Astrophysics Data System (ADS)

Obrien, J. C.; Howell, R. H.; Radousky, H. B.; Sterne, P. A.; Hinks, D. G.; Folkerts, T. J.; Shelton, R. N.

1990-12-01

Temperature-dependent positron lifetime experiments have been performed from room temperature to cryogenic temperatures on Ba(1-x)K(x)BiO3, for x = 0.4 and 0.5. From the temperature dependence of the positron lifetime in the normal state, we observe a clear signature of competition between separate defect populations to trap the positron. Theoretical calculations of lifetimes of free or trapped positrons have been performed on Ba(1-x)K(x)BiO3, to help identify these defects. Lifetime measurements separated by long times have been performed and evidence of aging effects in the sample defect populations is seen in these materials.

Phasor imaging with a widefield photon-counting detector

PubMed Central

Siegmund, Oswald H. W.; Tremsin, Anton S.; Vallerga, John V.; Weiss, Shimon

2012-01-01

Abstract. Fluorescence lifetime can be used as a contrast mechanism to distinguish fluorophores for localization or tracking, for studying molecular interactions, binding, assembly, and aggregation, or for observing conformational changes via Förster resonance energy transfer (FRET) between donor and acceptor molecules. Fluorescence lifetime imaging microscopy (FLIM) is thus a powerful technique but its widespread use has been hampered by demanding hardware and software requirements. FLIM data is often analyzed in terms of multicomponent fluorescence lifetime decays, which requires large signals for a good signal-to-noise ratio. This confines the approach to very low frame rates and limits the number of frames which can be acquired before bleaching the sample. Recently, a computationally efficient and intuitive graphical representation, the phasor approach, has been proposed as an alternative method for FLIM data analysis at the ensemble and single-molecule level. In this article, we illustrate the advantages of combining phasor analysis with a widefield time-resolved single photon-counting detector (the H33D detector) for FLIM applications. In particular we show that phasor analysis allows real-time subsecond identification of species by their lifetimes and rapid representation of their spatial distribution, thanks to the parallel acquisition of FLIM information over a wide field of view by the H33D detector. We also discuss possible improvements of the H33D detector’s performance made possible by the simplicity of phasor analysis and its relaxed timing accuracy requirements compared to standard time-correlated single-photon counting (TCSPC) methods. PMID:22352658

Application of phasor plot and autofluorescence correction for study of heterogeneous cell population

PubMed Central

Szmacinski, Henryk; Toshchakov, Vladimir; Lakowicz, Joseph R.

2014-01-01

Abstract. Protein-protein interactions in cells are often studied using fluorescence resonance energy transfer (FRET) phenomenon by fluorescence lifetime imaging microscopy (FLIM). Here, we demonstrate approaches to the quantitative analysis of FRET in cell population in a case complicated by a highly heterogeneous donor expression, multiexponential donor lifetime, large contribution of cell autofluorescence, and significant presence of unquenched donor molecules that do not interact with the acceptor due to low affinity of donor-acceptor binding. We applied a multifrequency phasor plot to visualize FRET FLIM data, developed a method for lifetime background correction, and performed a detailed time-resolved analysis using a biexponential model. These approaches were applied to study the interaction between the Toll Interleukin-1 receptor (TIR) domain of Toll-like receptor 4 (TLR4) and the decoy peptide 4BB. TLR4 was fused to Cerulean fluorescent protein (Cer) and 4BB peptide was labeled with Bodipy TMRX (BTX). Phasor displays for multifrequency FLIM data are presented. The analytical procedure for lifetime background correction is described and the effect of correction on FLIM data is demonstrated. The absolute FRET efficiency was determined based on the phasor plot display and multifrequency FLIM data analysis. The binding affinity between TLR4-Cer (donor) and decoy peptide 4BB-BTX (acceptor) was estimated in a heterogeneous HeLa cell population. PMID:24770662

2007 international meeting on Reduced Enrichment for Research and Test Reactors (RERTR). Abstracts and available papers presented at the meeting

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2008-07-15

The Meeting papers discuss research and test reactor fuel performance, manufacturing and testing. Some of the main topics are: conversion from HEU to LEU in different reactors and corresponding problems and activities; flux performance and core lifetime analysis with HEU and LEU fuels; physics and safety characteristics; measurement of gamma field parameters in core with LEU fuel; nondestructive analysis of RERTR fuel; thermal hydraulic analysis; fuel interactions; transient analyses and thermal hydraulics for HEU and LEU cores; microstructure research reactor fuels; post irradiation analysis and performance; computer codes and other related problems.

Introduction to basic solar cell measurements

NASA Technical Reports Server (NTRS)

Brandhorst, H. W., Jr.

1976-01-01

The basic approaches to solar cell performance and diagnostic measurements are described. The light sources, equipment for I-V curve measurement, and the test conditions and procedures for performance measurement are detailed. Solar cell diagnostic tools discussed include analysis of I-V curves, series resistance and reverse saturation current determination, spectral response/quantum yield measurement, and diffusion length/lifetime determination.

Lifetime testing results and diagnostic performance prediction of linear coolers at Thales Cryogenics

NASA Astrophysics Data System (ADS)

van der Weijden, H.; Benschop, T.; van de Groep, W.; Willems, D.

2011-06-01

Thales Cryogenics (TCBV) has an extensive background in delivering long-life cryogenic coolers for military, civil and space programs. During the last years many technical improvements have increased the lifetime of coolers resulting in significantly higher MTTF's. Lifetime endurance tests are used to validate these performance increases. An update will be given on lifetime test of a selection of TCBV's coolers. MTTF figures indicate the statistical average lifetimes for a large population of coolers. However, for the user of IR camera's and spectrometers a detailed view on the performance of an individual cooler and the possible impact of its performance degradation during its lifetime is very important. Thales Cryogenics is developing Cooler Diagnostic Software (CDS), which can be implemented in the firmware of its DSP based cooler drive electronics. With this implemented software the monitoring of the main cooler parameters during the lifetime in the equipment will be possible, including the prediction of the expected cooler performance availability. Based on this software it will be possible to analyze the status of the cooler inside the equipment and, supported by the lifetime knowledge at Thales Cryogenics, make essential choices on the maintenance of equipment and the replacement of coolers. In the paper, we will give an overview of potential situations in which such a predictive algorithm can be used. We will present the required interaction with future users to make an optimal interaction and interpretation of the generated data possible.

Life-cycle costs of high-performance cells

NASA Technical Reports Server (NTRS)

Daniel, R.; Burger, D.; Reiter, L.

1985-01-01

A life cycle cost analysis of high efficiency cells was presented. Although high efficiency cells produce more power, they also cost more to make and are more susceptible to array hot-spot heating. Three different computer analysis programs were used: SAMICS (solar array manufacturing industry costing standards), PVARRAY (an array failure mode/degradation simulator), and LCP (lifetime cost and performance). The high efficiency cell modules were found to be more economical in this study, but parallel redundancy is recommended.

Cost-effectiveness analysis of trastuzumab in the adjuvant setting for treatment of HER2-positive breast cancer.

PubMed

Garrison, Louis P; Lubeck, Deborah; Lalla, Deepa; Paton, Virginia; Dueck, Amylou; Perez, Edith A

2007-08-01

Adding trastuzumab to adjuvant chemotherapy provides significant clinical benefit in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. A cost-effectiveness analysis was performed to assess clinical and economic implications of adding trastuzumab to adjuvant chemotherapy, based upon joint analysis of NSABP B-31 and NCCTG N9831 trials. A Markov model with 4 health states was used to estimate the cost utility for a 50-year-old woman on the basis of trial results through 4 years and estimates of long-term recurrence and death based on a meta-analysis of trials. From 6 years onward, rates of recurrence and death were assumed to be the same in both trastuzumab and chemotherapy-only arms. Incremental costs were estimated for diagnostic and treatment-related costs. Analyses were from payer and societal perspectives, and these analyses were projected to lifetime and 20-year horizons. Over a lifetime, the projected cost of trastuzumab per quality-adjusted life year (QALY; discount rate 3%) gained was 26,417 dollars (range 9,104 dollars-69,340 dollars under multiway sensitivity analysis). Discounted incremental lifetime cost was 44,923 dollars, and projected life expectancy was 3 years longer for patients who received trastuzumab (19.4 years vs 16.4 years). During a 20-year horizon, the projected cost of adding trastuzumab to chemotherapy was 34,201 dollars per QALY gained. Key cost-effectiveness drivers were discount rate, trastuzumab price, and probability of metastasis. The cost-effectiveness result was robust to sensitivity analysis. Trastuzumab for adjuvant treatment of early stage breast cancer was projected to be cost effective over a lifetime horizon, achieving a cost-effectiveness ratio below that of many widely accepted oncology treatments. (c) 2007 American Cancer Society.

Perovskite-sensitized solar cells-based Ga-TiO2 nanodiatom-like photoanode: the improvement of performance by perovskite crystallinity refinement

NASA Astrophysics Data System (ADS)

Umar, Akrajas Ali; Al-She'irey, Altaf Yahya Ahmed; Rahman, Mohd Yusri Abd; Salleh, Muhamad Mat; Oyama, Munetaka

2018-05-01

The structure and crystallinity of the photoactive materials in solar cell determines the exciton formation, carrier's recombination, life-time and transportation in the devices. Here, we report that enhanced charge transportation, internal quantum efficiency and the carrier life-time can be achieved by modifying the structure, morphology of the organic perovskite thin film, enabling the improvement of the solar cell performance. The thin film structure modification was achieved via a thermal annealing in vacuum. In typical procedure, the power conversion efficiency of the PSC device can be upgraded from 0.5 to 2.9%, which is approximately 6 times increment, when the surface structure disorders are limited in the organic perovskite thin film. By optimizing the organic perovskite loading on the Ga-TiO2 diatom-like nanostructures photoanode and combining with a fine control of organic perovskite thin film structure, power conversion efficiency as high as 6.58% can be generated from the device. Electrochemical impedance spectroscopy and current-voltage analysis in the dark indicated that this process has effectively augmented the carrier life-time and limited the carrier recombination, enhancing the overall performance of the solar cell device. The preparation process and mechanism of the device performance improvement will be discussed.

Setting Performance Standards for a Cost-Effective Human Immunodeficiency Virus Cure Strategy in South Africa

PubMed Central

Paltiel, A. David; Zheng, Amy; Weinstein, Milton C.; Gaynes, Melanie R.; Wood, Robin; Freedberg, Kenneth A.; Sax, Paul E.

2017-01-01

Abstract Background. Reports of a single case of human immunodeficiency virus (HIV) eradication suggest that elimination of HIV from individuals is possible. Anticipating both increased research funding and the development of effective, durable cure technologies, we describe the circumstances under which a cure might improve survival and be cost-effective in South Africa. Methods. We adapted a simulation model comparing a hypothetical cure strategy (“Cure”) to the standard of care, lifetime antiretroviral therapy (“LifetimeART”) among adherent South Africans (58% female; mean age 33.8 years; mean CD4 257/µL; virologic suppression ≥1 year). We portrayed cure as a single intervention, producing sustained viral eradication without ART. We considered both a plausible, more imminently achievable “Baseline Scenario” and a more aspirational “Optimistic Scenario”. Inputs (Baseline/Optimistic) included the following: 50%/75% efficacy; 0.6%/0.0% fatal toxicity; 0.37%/0.085% monthly relapse over 5 years (0.185%/0.0425% per month thereafter); and $2000/$500 cost. These inputs were varied extensively in sensitivity analysis. Results. At baseline, Cure was “dominated,” yielding lower discounted life expectancy (19.31 life-years [LY] vs 19.37 LY) and greater discounted lifetime costs ($13 800 vs $13 700) than LifetimeART. Under optimistic assumptions, Cure was “cost-saving,” producing greater survival (19.91 LY) and lower lifetime costs ($11 000) than LifetimeART. Findings were highly sensitive to data assumptions, leaving little middle ground where a tradeoff existed between improved survival and higher costs. Conclusions. Only under the most favorable performance assumptions will an HIV cure strategy prove clinically and economically justifiable in South Africa. The scientific pursuit of a cure should not undermine continued expansions of access to proven, effective, and cost-effective ART. PMID:28680903

Cobalt related defect levels in silicon analyzed by temperature- and injection-dependent lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Diez, S.; Rein, S.; Roth, T.; Glunz, S. W.

2007-02-01

Temperature- and injection-dependent lifetime spectroscopy (TIDLS) as a method to characterize point defects in silicon with several energy levels is demonstrated. An intentionally cobalt-contaminated p-type wafer was investigated by means of lifetime measurements performed at different temperatures up to 151°C. Two defect energy levels were required to model the lifetime curves on basis of the Shockley-Read-Hall statistics. The detailed analysis is based on the determination of the recently introduced defect parameter solution surface (DPSS) in order to extract the underlying defect parameters. A unique solution has been found for a deep defect level located in the upper band gap half with an energy depth of EC-Et=0.38±0.01eV, with a corresponding ratio of capture cross sections k =σn/σp=0.16 within the interval of uncertainty of 0.06-0.69. Additionally, a deep donor level in the lower band gap half known from the literature could be assigned to a second energy level within the DPSS analysis at Et-EV=0.41±0.02eV with a corresponding ratio of capture cross sections k =σn/σp=16±3. An investigation of the temperature dependence of the capture cross section for electrons suggests that the underlying recombination process of the defect in the lower band gap half is driven by a two stage cascade capture with an activation energy of ΔE =52±2meV. These results show that TIDLS in combination with DPSS analysis is a powerful method to characterize even multiple defect levels that are affecting carrier recombination lifetime in parallel.

Pelvic Floor Consequences of Cesarean Delivery on Maternal Request in Women with a Single Birth: A Cost-effectiveness Analysis

PubMed Central

Ivy, Julie S.; Patel, Divya A.; Patel, Sejal N.; Smith, Dean G.; Ransom, Scott B.; Fenner, Dee; DeLancey, John O.L.

2010-01-01

Abstract Background The potential benefit in preventing pelvic floor disorders (PFDs) is a frequently cited reason for requesting or performing cesarean delivery on maternal request (CDMR). However, for primigravid women without medical/obstetric indications, the lifetime cost-effectiveness of CDMR remains unknown, particularly with regard to lifelong pelvic floor consequences. Our objective was to assess the cost-effectiveness of CDMR in comparison to trial of labor (TOL) for primigravid women without medical/obstetric indications with a single childbirth over their lifetime, while explicitly accounting for the management of PFD throughout the lifetime. Methods We used Monte Carlo simulation of a decision model containing 249 chance events and 101 parameters depicting lifelong maternal and neonatal outcomes in the following domains: actual mode of delivery, emergency hysterectomy, transient maternal morbidity and mortality, perinatal morbidity and mortality, and the lifelong management of PFDs. Parameter estimates were obtained from published literature. The analysis was conducted from a societal perspective. All costs and quality-adjusted life-years (QALYs) were discounted to the present value at childbirth. Results The estimated mean cost and QALYs were $14,259 (95% confidence interval [CI] $8,964-$24,002) and 58.21 (95% CI 57.43-58.67) for CDMR and $13,283 (95% CI $7,861-$23,829) and 57.87 (95% CI 56.97-58.46) for TOL over the combined lifetime of the mother and the child. Parameters related to PFDs play an important role in determining cost and quality of life. Conclusions When a woman without medical/obstetric indications has only one childbirth in her lifetime, cost-effectiveness analysis does not reveal a clearly preferable mode of delivery. PMID:20088671

Stochastic Modeling and Analysis of Multiple Nonlinear Accelerated Degradation Processes through Information Fusion

PubMed Central

Sun, Fuqiang; Liu, Le; Li, Xiaoyang; Liao, Haitao

2016-01-01

Accelerated degradation testing (ADT) is an efficient technique for evaluating the lifetime of a highly reliable product whose underlying failure process may be traced by the degradation of the product’s performance parameters with time. However, most research on ADT mainly focuses on a single performance parameter. In reality, the performance of a modern product is usually characterized by multiple parameters, and the degradation paths are usually nonlinear. To address such problems, this paper develops a new s-dependent nonlinear ADT model for products with multiple performance parameters using a general Wiener process and copulas. The general Wiener process models the nonlinear ADT data, and the dependency among different degradation measures is analyzed using the copula method. An engineering case study on a tuner’s ADT data is conducted to demonstrate the effectiveness of the proposed method. The results illustrate that the proposed method is quite effective in estimating the lifetime of a product with s-dependent performance parameters. PMID:27509499

Stochastic Modeling and Analysis of Multiple Nonlinear Accelerated Degradation Processes through Information Fusion.

PubMed

Sun, Fuqiang; Liu, Le; Li, Xiaoyang; Liao, Haitao

2016-08-06

Accelerated degradation testing (ADT) is an efficient technique for evaluating the lifetime of a highly reliable product whose underlying failure process may be traced by the degradation of the product's performance parameters with time. However, most research on ADT mainly focuses on a single performance parameter. In reality, the performance of a modern product is usually characterized by multiple parameters, and the degradation paths are usually nonlinear. To address such problems, this paper develops a new s-dependent nonlinear ADT model for products with multiple performance parameters using a general Wiener process and copulas. The general Wiener process models the nonlinear ADT data, and the dependency among different degradation measures is analyzed using the copula method. An engineering case study on a tuner's ADT data is conducted to demonstrate the effectiveness of the proposed method. The results illustrate that the proposed method is quite effective in estimating the lifetime of a product with s-dependent performance parameters.

In Situ Analysis of Gas Generation in Lithium-Ion Batteries with Different Carbonate-Based Electrolytes.

PubMed

Teng, Xin; Zhan, Chun; Bai, Ying; Ma, Lu; Liu, Qi; Wu, Chuan; Wu, Feng; Yang, Yusheng; Lu, Jun; Amine, Khalil

2015-10-21

Gas generation in lithium-ion batteries is one of the critical issues limiting their safety performance and lifetime. In this work, a set of 900 mAh pouch cells were applied to systematically compare the composition of gases generated from a serial of carbonate-based composite electrolytes, using a self-designed gas analyzing system. Among electrolytes used in this work, the composite γ-butyrolactone/ethyl methyl carbonate (GBL/EMC) exhibited remarkably less gassing because of the electrochemical stability of the GBL, which makes it a promising electrolyte for battery with advanced safety and lifetime.

Tomographic Positron Annihilation Lifetime Spectroscopy

NASA Astrophysics Data System (ADS)

Wagner, A.; Anwand, W.; Butterling, M.; Fiedler, F.; Fritz, F.; Kempe, M.; Cowan, T. E.

2014-04-01

Positron annihilation lifetime spectroscopy serves as a perfect tool for studies of open-volume defects in solid materials such as vacancies, vacancy agglomerates, and dislocations. Moreover, structures in porous media can be investigated ranging from 0.3 nm to 30 nm employing the variation of the Positronium lifetime with the pore size. While lifetime measurements close to the material's surface can be performed at positron-beam installations bulk materials, fluids, bio-materials or composite structures cannot or only destructively accessed by positron beams. Targeting those problems, a new method of non-destructive positron annihilation lifetime spectroscopy has been developed which features even a 3-dimensional tomographic reconstruction of the spatial lifetime distribution. A beam of intense bremsstrahlung is provided by the superconducting electron linear accelerator ELBE (Electron Linear Accelerator with high Brilliance and low Emittance) at Helmholtz-Zentrum Dresden-Rossendorf. Since the generation of bremsstrahlung and the transport to the sample preserves the sharp timing of the electron beam, positrons generated inside the entire sample volume by pair production feature a sharp start time stamp for lifetime studies. In addition to the existing technique of in-situ production of positrons inside large (cm3) bulk samples using high-energy photons up to 16 MeV from bremsstrahlung production, granular position-sensitive photon detectors have been employed. The detector system will be described and results for experiments using samples with increasing complexity will be presented. The Lu2SiO5:Ce scintillation crystals allow resolving the total energy to 5.1 % (root-mean-square, RMS) and the annihilation lifetime to 225 ps (RMS). 3-dimensional annihilation lifetime maps have been created in an offline-analysis employing well-known techniques from PET.

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE PAGES

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris; ...

2017-04-26

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

Extension lifetime for dye-sensitized solar cells through multiple dye adsorption/desorption process

NASA Astrophysics Data System (ADS)

Chiang, Yi-Fang; Chen, Ruei-Tang; Shen, Po-Shen; Chen, Peter; Guo, Tzung-Fang

2013-03-01

In this study, we propose a novel concept of extending the lifetime of dye-sensitized solar cells (DSCs) and reducing the costs of re-conditioning DSCs by recycling the FTO/TiO2 substrates. The photovoltaic performances of DSCs using substrates with various cycles of dye uptake and rinse off history are tested. The results show that dye adsorption and Voc are significantly increased under multiple dye adsorption/desorption process and resulted in the improvement of power conversion efficiency. Moreover, the dyeing kinetics is faster after multiple recycling processes, which is favorable for the industrial application. With surface analysis and charge transport characteristics, we also demonstrate the optimal functionality of TiO2/dye interface for the improved Voc and efficiency. The results confirm that the improved performances are due to increased dye loading and dense packing of dye molecules. Our results are beneficial for the understanding on the extension of DSCs lifetime after long-term operation in the application of DSC modules. This approach may also be applied in the replacement of newly synthesized photosensitizes to the active cells.

Analgesics use and ESRD in younger age: a case-control study

PubMed Central

van der Woude, Fokke J; Heinemann, Lothar AJ; Graf, Helmut; Lewis, Michael; Moehner, Sabine; Assmann, Anita; Kühl-Habich, Doerthe

2007-01-01

Background An ad hoc peer-review committee was jointly appointed by Drug Authorities and Industry in Germany, Austria and Switzerland in 1999/2000 to review the evidence for a causal relation between phenacetin-free analgesics and nephropathy. The committee found the evidence as inconclusive and requested a new case-control study of adequate design. Methods We performed a population-based case-control study with incident cases of end-stage renal disease (ESRD) under the age of 50 years and four age and sex-matched neighborhood controls in 170 dialysis centers (153 in Germany, and 17 in Austria) from January 1, 2001 to December 31, 2004. Data on lifetime medical history, risk factors, treatment, job exposure and intake of analgesics were obtained in a standardized face-to-face interview using memory aids to enhance accuracy. Study design, study performance, analysis plan, and study report were approved by an independent international advisory committee and by the Drug Authorities involved. Unconditional logistic regression analyses were performed. Results The analysis included 907 cases and 3,622 controls who had never used phenacetin-containing analgesics in their lifetime. The use of high cumulative lifetime dose (3rd tertile) of analgesics in the period up to five years before dialysis was not associated with later ESRD. Adjusted odds ratios with 95% confidence intervals were 0.8 (0.7 – 1.0) and 1.0 (0.8 – 1.3) for ever- compared with no or low use and high use compared with low use, respectively. The same results were found for all analgesics and for mono-, and combination preparations with and without caffeine. No increased risk was shown in analyses stratifying for dose and duration. Dose-response analyses showed that analgesic use was not associated with an increased risk for ESRD up to 3.5 kg cumulative lifetime dose (98 % of the cases with ESRD). While the large subgroup of users with a lifetime dose up to 0.5 kg (278 cases and 1365 controls) showed a significantly decreased risk, a tiny subgroup of extreme users with over 3.5 kg lifetime use (19 cases and 11 controls) showed a significant risk increase. The detailed evaluation of 22 cases and 19 controls with over 2.5 kg lifetime use recommended by the regulatory advisors showed an impressive excess of other conditions than analgesics triggering the evolution of ESRD in cases compared with controls. Conclusion We found no clinically meaningful evidence for an increased risk of ESRD associated with use of phenacetin-free analgesics in single or combined formulation. The apparent risk increase shown in a small subgroup with extreme lifetime dose of analgesics is most likely an indirect, non-causal association. This hypothesis, however, cannot be confirmed or refuted within our case-control study. Overall, our results lend support to the mounting evidence that phenacetin-free analgesics do not induce ESRD and that the notion of "analgesic nephropathy" needs to be re-evaluated. PMID:18053232

Pulsed food resources, but not forest cover, determine lifetime reproductive success in a forest-dwelling rodent.

PubMed

Hoset, Katrine S; Villers, Alexandre; Wistbacka, Ralf; Selonen, Vesa

2017-09-01

The relative contributions of habitat and food availability on fitness may provide evidence for key habitat features needed to safeguard population persistence. However, defining habitat quality for a species can be a complex task, especially if knowledge on the relationship between individual performance and habitat quality is lacking. Here, we determined the relative importance of the availability of suitable forest habitat, body mass and food from masting tree species on female lifetime reproductive success (LRS) of Siberian flying squirrels (Pteromys volans). We calculated LRS of 500 female flying squirrels based on a 22-year-long longitudinal dataset of two populations from western Finland. We assessed with generalised additive models the potential effects of availability of suitable habitat and cumulative lifetime availability of food from masting tree species on female LRS, longevity and fecundity. On a reduced dataset, we evaluated the importance of female winter body mass and conducted a piecewise path analysis to determine how variables were connected. According to generalised additive models female longevity, fecundity and LRS were mainly determined by variation in cumulative lifetime availability of food from masting alder and birch. Instead, habitat and body mass had a smaller role. The path analysis indicated that lifetime food availability had a direct effect on longevity and fecundity, and these had an equal effect on LRS at both study sites. Our results on LRS show that the occurrence of tree masting events during a female flying squirrel's lifetime has a profoundly larger effect on LRS than the cover of suitable forest habitat. Furthermore, this study emphasises the importance of both fecundity and longevity, and the indirect effects of food availability via those components, as determinants of lifetime fitness in female flying squirrels. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Genome-wide association study of lifetime cannabis use based on a large meta-analytic sample of 32 330 subjects from the International Cannabis Consortium

PubMed Central

Stringer, S; Minică, C C; Verweij, K J H; Mbarek, H; Bernard, M; Derringer, J; van Eijk, K R; Isen, J D; Loukola, A; Maciejewski, D F; Mihailov, E; van der Most, P J; Sánchez-Mora, C; Roos, L; Sherva, R; Walters, R; Ware, J J; Abdellaoui, A; Bigdeli, T B; Branje, S J T; Brown, S A; Bruinenberg, M; Casas, M; Esko, T; Garcia-Martinez, I; Gordon, S D; Harris, J M; Hartman, C A; Henders, A K; Heath, A C; Hickie, I B; Hickman, M; Hopfer, C J; Hottenga, J J; Huizink, A C; Irons, D E; Kahn, R S; Korhonen, T; Kranzler, H R; Krauter, K; van Lier, P A C; Lubke, G H; Madden, P A F; Mägi, R; McGue, M K; Medland, S E; Meeus, W H J; Miller, M B; Montgomery, G W; Nivard, M G; Nolte, I M; Oldehinkel, A J; Pausova, Z; Qaiser, B; Quaye, L; Ramos-Quiroga, J A; Richarte, V; Rose, R J; Shin, J; Stallings, M C; Stiby, A I; Wall, T L; Wright, M J; Koot, H M; Paus, T; Hewitt, J K; Ribasés, M; Kaprio, J; Boks, M P; Snieder, H; Spector, T; Munafò, M R; Metspalu, A; Gelernter, J; Boomsma, D I; Iacono, W G; Martin, N G; Gillespie, N A; Derks, E M; Vink, J M

2016-01-01

Cannabis is the most widely produced and consumed illicit psychoactive substance worldwide. Occasional cannabis use can progress to frequent use, abuse and dependence with all known adverse physical, psychological and social consequences. Individual differences in cannabis initiation are heritable (40–48%). The International Cannabis Consortium was established with the aim to identify genetic risk variants of cannabis use. We conducted a meta-analysis of genome-wide association data of 13 cohorts (N=32 330) and four replication samples (N=5627). In addition, we performed a gene-based test of association, estimated single-nucleotide polymorphism (SNP)-based heritability and explored the genetic correlation between lifetime cannabis use and cigarette use using LD score regression. No individual SNPs reached genome-wide significance. Nonetheless, gene-based tests identified four genes significantly associated with lifetime cannabis use: NCAM1, CADM2, SCOC and KCNT2. Previous studies reported associations of NCAM1 with cigarette smoking and other substance use, and those of CADM2 with body mass index, processing speed and autism disorders, which are phenotypes previously reported to be associated with cannabis use. Furthermore, we showed that, combined across the genome, all common SNPs explained 13–20% (P<0.001) of the liability of lifetime cannabis use. Finally, there was a strong genetic correlation (rg=0.83; P=1.85 × 10−8) between lifetime cannabis use and lifetime cigarette smoking implying that the SNP effect sizes of the two traits are highly correlated. This is the largest meta-analysis of cannabis GWA studies to date, revealing important new insights into the genetic pathways of lifetime cannabis use. Future functional studies should explore the impact of the identified genes on the biological mechanisms of cannabis use. PMID:27023175

Temporal binning of time-correlated single photon counting data improves exponential decay fits and imaging speed

PubMed Central

Walsh, Alex J.; Sharick, Joe T.; Skala, Melissa C.; Beier, Hope T.

2016-01-01

Time-correlated single photon counting (TCSPC) enables acquisition of fluorescence lifetime decays with high temporal resolution within the fluorescence decay. However, many thousands of photons per pixel are required for accurate lifetime decay curve representation, instrument response deconvolution, and lifetime estimation, particularly for two-component lifetimes. TCSPC imaging speed is inherently limited due to the single photon per laser pulse nature and low fluorescence event efficiencies (<10%) required to reduce bias towards short lifetimes. Here, simulated fluorescence lifetime decays are analyzed by SPCImage and SLIM Curve software to determine the limiting lifetime parameters and photon requirements of fluorescence lifetime decays that can be accurately fit. Data analysis techniques to improve fitting accuracy for low photon count data were evaluated. Temporal binning of the decays from 256 time bins to 42 time bins significantly (p<0.0001) improved fit accuracy in SPCImage and enabled accurate fits with low photon counts (as low as 700 photons/decay), a 6-fold reduction in required photons and therefore improvement in imaging speed. Additionally, reducing the number of free parameters in the fitting algorithm by fixing the lifetimes to known values significantly reduced the lifetime component error from 27.3% to 3.2% in SPCImage (p<0.0001) and from 50.6% to 4.2% in SLIM Curve (p<0.0001). Analysis of nicotinamide adenine dinucleotide–lactate dehydrogenase (NADH-LDH) solutions confirmed temporal binning of TCSPC data and a reduced number of free parameters improves exponential decay fit accuracy in SPCImage. Altogether, temporal binning (in SPCImage) and reduced free parameters are data analysis techniques that enable accurate lifetime estimation from low photon count data and enable TCSPC imaging speeds up to 6x and 300x faster, respectively, than traditional TCSPC analysis. PMID:27446663

Lifetime Alcohol Use & Cognitive Performance in Older Adults

PubMed Central

Kalapatapu, Raj K.; Ventura, Maria I.; Barnes, Deborah E.

2016-01-01

Background Substance use is an important clinical issue in the older adult population. As older adults are susceptible to cognitive disorders, the intersection of the fields of substance use and cognitive neuroscience is an active area of research. Prior studies of alcohol use and cognitive performance are mixed, and inconsistencies may be due to under- or over-adjustment for confounders. Aim This manuscript adds to this literature by conducting a secondary analysis of self-reported lifetime history of alcohol use and cognitive performance in older adults (n = 133). We hypothesized that current alcohol users would have poorer cognitive performance compared to never/minimal and former alcohol users. Methods Older adult participants were classified into never/minimal alcohol users, former alcohol users, and current alcohol users. A neurocognitive battery included a global cognitive measure and individual measures of attention, memory, fluency, and executive function. A directed acyclic graph (DAG)-based approach was used to select variables to be included in the multiple linear regression models. Results Though unadjusted analyses showed some significant associations between alcohol use and cognitive performance, all associations between alcohol use and cognitive performance were eliminated after adjusting for age, education, sex, race and smoking pack years. Alcohol drink years were not significantly associated with cognitive performance among current and former alcohol users. Discussion These results suggest that lifetime alcohol use is not significantly associated with cognitive performance in older adults after adjustment for key confounders. Inconsistencies in prior studies may be due to uncontrolled confounding and/or unnecessary adjustment of mediators and/or colliders. PMID:27719514

Temporal and spatial binning of TCSPC data to improve signal-to-noise ratio and imaging speed

NASA Astrophysics Data System (ADS)

Walsh, Alex J.; Beier, Hope T.

2016-03-01

Time-correlated single photon counting (TCSPC) is the most robust method for fluorescence lifetime imaging using laser scanning microscopes. However, TCSPC is inherently slow making it ineffective to capture rapid events due to the single photon product per laser pulse causing extensive acquisition time limitations and the requirement of low fluorescence emission efficiency to avoid bias of measurement towards short lifetimes. Furthermore, thousands of photons per pixel are required for traditional instrument response deconvolution and fluorescence lifetime exponential decay estimation. Instrument response deconvolution and fluorescence exponential decay estimation can be performed in several ways including iterative least squares minimization and Laguerre deconvolution. This paper compares the limitations and accuracy of these fluorescence decay analysis techniques to accurately estimate double exponential decays across many data characteristics including various lifetime values, lifetime component weights, signal-to-noise ratios, and number of photons detected. Furthermore, techniques to improve data fitting, including binning data temporally and spatially, are evaluated as methods to improve decay fits and reduce image acquisition time. Simulation results demonstrate that binning temporally to 36 or 42 time bins, improves accuracy of fits for low photon count data. Such a technique reduces the required number of photons for accurate component estimation if lifetime values are known, such as for commercial fluorescent dyes and FRET experiments, and improve imaging speed 10-fold.

FLIMX: A Software Package to Determine and Analyze the Fluorescence Lifetime in Time-Resolved Fluorescence Data from the Human Eye.

PubMed

Klemm, Matthias; Schweitzer, Dietrich; Peters, Sven; Sauer, Lydia; Hammer, Martin; Haueisen, Jens

2015-01-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique for measuring the in vivo autofluorescence intensity decays generated by endogenous fluorophores in the ocular fundus. Here, we present a software package called FLIM eXplorer (FLIMX) for analyzing FLIO data. Specifically, we introduce a new adaptive binning approach as an optimal tradeoff between the spatial resolution and the number of photons required per pixel. We also expand existing decay models (multi-exponential, stretched exponential, spectral global analysis, incomplete decay) to account for the layered structure of the eye and present a method to correct for the influence of the crystalline lens fluorescence on the retina fluorescence. Subsequently, the Holm-Bonferroni method is applied to FLIO measurements to allow for group comparisons between patients and controls on the basis of fluorescence lifetime parameters. The performance of the new approaches was evaluated in five experiments. Specifically, we evaluated static and adaptive binning in a diabetes mellitus patient, we compared the different decay models in a healthy volunteer and performed a group comparison between diabetes patients and controls. An overview of the visualization capabilities and a comparison of static and adaptive binning is shown for a patient with macular hole. FLIMX's applicability to fluorescence lifetime imaging microscopy is shown in the ganglion cell layer of a porcine retina sample, obtained by a laser scanning microscope using two-photon excitation.

The cost-effectiveness of telestroke in the treatment of acute ischemic stroke

PubMed Central

Nelson, R.E.; Saltzman, G.M.; Skalabrin, E.J.; Demaerschalk, B.M.

2011-01-01

Objective: To conduct a cost-effectiveness analysis of telestroke—a 2-way, audiovisual technology that links stroke specialists to remote emergency department physicians and their stroke patients—compared to usual care (i.e., remote emergency departments without telestroke consultation or stroke experts). Methods: A decision-analytic model was developed for both 90-day and lifetime horizons. Model inputs were taken from published literature where available and supplemented with western states' telestroke experiences. Costs were gathered using a societal perspective and converted to 2008 US dollars. Quality-adjusted life-years (QALYs) gained were combined with costs to generate incremental cost-effectiveness ratios (ICERs). In the lifetime horizon model, both costs and QALYs were discounted at 3% annually. Both one-way sensitivity analyses and Monte Carlo simulations were performed. Results: In the base case analysis, compared to usual care, telestroke results in an ICER of $108,363/QALY in the 90-day horizon and $2,449/QALY in the lifetime horizon. For the 90-day and lifetime horizons, 37.5% and 99.7% of 10,000 Monte Carlo simulations yielded ICERs <$50,000/QALY, a ratio commonly considered acceptable in the United States. Conclusion: When a lifetime perspective is taken, telestroke appears cost-effective compared to usual care, since telestroke costs are upfront but benefits of improved stroke care are lifelong. If barriers to use such as low reimbursement rates and high equipment costs are reduced, telestroke has the potential to diminish the striking geographic disparities of acute stroke care in the United States. PMID:21917781

Modelling impacts of performance on the probability of reproducing, and thereby on productive lifespan, allow prediction of lifetime efficiency in dairy cows.

PubMed

Phuong, H N; Blavy, P; Martin, O; Schmidely, P; Friggens, N C

2016-01-01

Reproductive success is a key component of lifetime efficiency - which is the ratio of energy in milk (MJ) to energy intake (MJ) over the lifespan, of cows. At the animal level, breeding and feeding management can substantially impact milk yield, body condition and energy balance of cows, which are known as major contributors to reproductive failure in dairy cattle. This study extended an existing lifetime performance model to incorporate the impacts that performance changes due to changing breeding and feeding strategies have on the probability of reproducing and thereby on the productive lifespan, and thus allow the prediction of a cow's lifetime efficiency. The model is dynamic and stochastic, with an individual cow being the unit modelled and one day being the unit of time. To evaluate the model, data from a French study including Holstein and Normande cows fed high-concentrate diets and data from a Scottish study including Holstein cows selected for high and average genetic merit for fat plus protein that were fed high- v. low-concentrate diets were used. Generally, the model consistently simulated productive and reproductive performance of various genotypes of cows across feeding systems. In the French data, the model adequately simulated the reproductive performance of Holsteins but significantly under-predicted that of Normande cows. In the Scottish data, conception to first service was comparably simulated, whereas interval traits were slightly under-predicted. Selection for greater milk production impaired the reproductive performance and lifespan but not lifetime efficiency. The definition of lifetime efficiency used in this model did not include associated costs or herd-level effects. Further works should include such economic indicators to allow more accurate simulation of lifetime profitability in different production scenarios.

Eco-efficiency evaluation of a smart window prototype.

PubMed

Syrrakou, E; Papaefthimiou, S; Yianoulis, P

2006-04-15

An eco-efficiency analysis was conducted using indicators suitably defined to evaluate the performance of an electrochromic window acting as an energy saving component in buildings. Combining the indicators for various parameters (control scenario, expected lifetime, climatic type, purchase cost) significant conclusions are drawn for the development and the potential applications of the device compared to other commercial fenestration products. The reduction of the purchase cost (to 200 euros/m2) and the increase of the lifetime (above 15 years) are the two main targets for achieving both cost and environmental efficiency. An electrochromic device, implemented in cooling dominated areas and operated with an optimum control strategy for the maximum expected lifetime (25 years), can reduce the building energy requirements by 52%. Furthermore, the total energy savings provided will be 33 times more than the energy required for its production while the emission of 615 kg CO2 equivalent per electrochromic glazing unit can be avoided.

The use of wind data with an operational wind turbine in a research and development environment

NASA Technical Reports Server (NTRS)

Neustadter, H. E.

1979-01-01

The status of the use of wind information is presented in four areas, namely: operational control, design verification, power performance analysis, and lifetime estimation. Attention is given to some of the identified wind information needs and the steps taken to meet these needs.

Advances in Plexcore active layer technology systems for organic photovoltaics: roof-top and accelerated lifetime analysis of high performance organic photovoltaic cells

NASA Astrophysics Data System (ADS)

Laird, Darin W.; Vaidya, Swanand; Li, Sergey; Mathai, Mathew; Woodworth, Brian; Sheina, Elena; Williams, Shawn; Hammond, Troy

2007-09-01

We report NREL-certified efficiencies and initial lifetime data for organic photovoltaic (OPV) cells based on Plexcore PV photoactive layer and Plexcore HTL-OPV hole transport layer technology. Plexcore PV-F3, a photoactive layer OPV ink, was certified in a single-layer OPV cell at the National Renewable Energy Laboratory (NREL) at 5.4%, which represents the highest official mark for a single-layer organic solar cell. We have fabricated and measured P3HT:PCBM solar cells with a peak efficiency of 4.4% and typical efficiencies of 3 - 4% (internal, NREL-calibrated measurement) with P3HT manufactured at Plextronics by the Grignard Metathesis (GRIM) method. Outdoor and accelerated lifetime testing of these devices is reported. Both Plexcore PV-F3 and P3HT:PCBM-based OPV cells exhibit >750 hours of outdoor roof-top, non-accelerated lifetime with less than 8% loss in initial efficiency for both active layer systems when exposed continuously to the climate of Western Pennsylvania. These devices are continuously being tested to date. Accelerated testing using a high-intensity (1000W) metal-halide lamp affords shorter lifetimes; however, the true acceleration factor is still to be determined.

Obsessional personality features in employed Japanese adults with a lifetime history of depression: assessment by the Munich Personality Test (MPT).

PubMed

Sakado, K; Sakado, M; Seki, T; Kuwabara, H; Kojima, M; Sato, T; Someya, T

2001-06-01

Although a number of studies have reported on the association between obsessional personality features as measured by the Munich Personality Test (MPT) "Rigidity" scale and depression, there has been no examination of these relationships in a non-clinical sample. The dimensional scores on the MPT were compared between subjects with and without lifetime depression, using a sample of employed Japanese adults. The odds ratio for suffering from lifetime depression was estimated by multiple logistic regression analysis. To diagnose a lifetime history of depression, the Inventory to Diagnose Depression, Lifetime version (IDDL) was used. The subjects with lifetime depression scored significantly higher on the "Rigidity" scale than the subjects without lifetime depression. In our logistic regression analysis, three risk factors were identified as each independently increasing a person's risk for suffering from lifetime depression: higher levels of "Rigidity", being of the female gender, and suffering from current depressive symptoms. The MPT "Rigidity" scale is a sensitive measure of personality features that occur with depression.

Origin of long lifetime of band-edge charge carriers in organic–inorganic lead iodide perovskites

PubMed Central

Chen, Tianran; Chen, Wei-Liang; Foley, Benjamin J.; Lee, Jooseop; Ruff, Jacob P. C.; Ko, J. Y. Peter; Brown, Craig M.; Harriger, Leland W.; Zhang, Depei; Park, Changwon; Yoon, Mina; Chang, Yu-Ming; Choi, Joshua J.; Lee, Seung-Hun

2017-01-01

Long carrier lifetime is what makes hybrid organic–inorganic perovskites high-performance photovoltaic materials. Several microscopic mechanisms behind the unusually long carrier lifetime have been proposed, such as formation of large polarons, Rashba effect, ferroelectric domains, and photon recycling. Here, we show that the screening of band-edge charge carriers by rotation of organic cation molecules can be a major contribution to the prolonged carrier lifetime. Our results reveal that the band-edge carrier lifetime increases when the system enters from a phase with lower rotational entropy to another phase with higher entropy. These results imply that the recombination of the photoexcited electrons and holes is suppressed by the screening, leading to the formation of polarons and thereby extending the lifetime. Thus, searching for organic–inorganic perovskites with high rotational entropy over a wide range of temperature may be a key to achieve superior solar cell performance. PMID:28673975

Origin of long lifetime of band-edge charge carriers in organic-inorganic lead iodide perovskites.

PubMed

Chen, Tianran; Chen, Wei-Liang; Foley, Benjamin J; Lee, Jooseop; Ruff, Jacob P C; Ko, J Y Peter; Brown, Craig M; Harriger, Leland W; Zhang, Depei; Park, Changwon; Yoon, Mina; Chang, Yu-Ming; Choi, Joshua J; Lee, Seung-Hun

2017-07-18

Long carrier lifetime is what makes hybrid organic-inorganic perovskites high-performance photovoltaic materials. Several microscopic mechanisms behind the unusually long carrier lifetime have been proposed, such as formation of large polarons, Rashba effect, ferroelectric domains, and photon recycling. Here, we show that the screening of band-edge charge carriers by rotation of organic cation molecules can be a major contribution to the prolonged carrier lifetime. Our results reveal that the band-edge carrier lifetime increases when the system enters from a phase with lower rotational entropy to another phase with higher entropy. These results imply that the recombination of the photoexcited electrons and holes is suppressed by the screening, leading to the formation of polarons and thereby extending the lifetime. Thus, searching for organic-inorganic perovskites with high rotational entropy over a wide range of temperature may be a key to achieve superior solar cell performance.

The global prevalence and correlates of skin bleaching: a meta-analysis and meta-regression analysis.

PubMed

Sagoe, Dominic; Pallesen, Ståle; Dlova, Ncoza C; Lartey, Margaret; Ezzedine, Khaled; Dadzie, Ophelia

2018-06-11

To estimate and investigate the global lifetime prevalence and correlates of skin bleaching. A meta-analysis and meta-regression analysis was performed based on a systematic and comprehensive literature search conducted in Google Scholar, ISI Web of Science, ProQuest, PsycNET, PubMed, and other relevant websites and reference lists. A total of 68 studies (67,665 participants) providing original data on the lifetime prevalence of skin bleaching were included. Publication bias was corrected using the trim and fill procedure. The pooled (imputed) lifetime prevalence of skin bleaching was 27.7% (95% CI: 19.6-37.5, I 2  = 99.6, P < 0.01). The highest significant prevalences were associated with: males (28.0%), topical corticosteroid use (51.8%), Africa (27.1%), persons aged ≤30 years (55.9%), individuals with only primary school education (31.6%), urban or semiurban residents (74.9%), patients (21.3%), data from 2010-2017 (26.8%), dermatological evaluation and testing-based assessment (24.9%), random sampling methods (29.2%), and moderate quality studies (32.3%). The proportion of females in study samples was significantly related to skin bleaching prevalence. Despite some limitations, our results indicate that the practice of skin bleaching is a serious global public health issue that should be addressed through appropriate public health interventions. © 2018 The International Society of Dermatology.

Cost effectiveness analysis comparing repetitive transcranial magnetic stimulation to antidepressant medications after a first treatment failure for major depressive disorder in newly diagnosed patients - A lifetime analysis.

PubMed

Voigt, Jeffrey; Carpenter, Linda; Leuchter, Andrew

2017-01-01

Repetitive Transcranial Magnetic Stimulation (rTMS) commonly is used for the treatment of Major Depressive Disorder (MDD) after patients have failed to benefit from trials of multiple antidepressant medications. No analysis to date has examined the cost-effectiveness of rTMS used earlier in the course of treatment and over a patients' lifetime. We used lifetime Markov simulation modeling to compare the direct costs and quality adjusted life years (QALYs) of rTMS and medication therapy in patients with newly diagnosed MDD (ages 20-59) who had failed to benefit from one pharmacotherapy trial. Patients' life expectancies, rates of response and remission, and quality of life outcomes were derived from the literature, and treatment costs were based upon published Medicare reimbursement data. Baseline costs, aggregate per year quality of life assessments (QALYs), Monte Carlo simulation, tornado analysis, assessment of dominance, and one way sensitivity analysis were also performed. The discount rate applied was 3%. Lifetime direct treatment costs, and QALYs identified rTMS as the dominant therapy compared to antidepressant medications (i.e., lower costs with better outcomes) in all age ranges, with costs/improved QALYs ranging from $2,952/0.32 (older patients) to $11,140/0.43 (younger patients). One-way sensitivity analysis demonstrated that the model was most sensitive to the input variables of cost per rTMS session, monthly prescription drug cost, and the number of rTMS sessions per year. rTMS was identified as the dominant therapy compared to antidepressant medication trials over the life of the patient across the lifespan of adults with MDD, given current costs of treatment. These models support the use of rTMS after a single failed antidepressant medication trial versus further attempts at medication treatment in adults with MDD.

Cost effectiveness analysis comparing repetitive transcranial magnetic stimulation to antidepressant medications after a first treatment failure for major depressive disorder in newly diagnosed patients – A lifetime analysis

PubMed Central

2017-01-01

Objective Repetitive Transcranial Magnetic Stimulation (rTMS) commonly is used for the treatment of Major Depressive Disorder (MDD) after patients have failed to benefit from trials of multiple antidepressant medications. No analysis to date has examined the cost-effectiveness of rTMS used earlier in the course of treatment and over a patients’ lifetime. Methods We used lifetime Markov simulation modeling to compare the direct costs and quality adjusted life years (QALYs) of rTMS and medication therapy in patients with newly diagnosed MDD (ages 20–59) who had failed to benefit from one pharmacotherapy trial. Patients’ life expectancies, rates of response and remission, and quality of life outcomes were derived from the literature, and treatment costs were based upon published Medicare reimbursement data. Baseline costs, aggregate per year quality of life assessments (QALYs), Monte Carlo simulation, tornado analysis, assessment of dominance, and one way sensitivity analysis were also performed. The discount rate applied was 3%. Results Lifetime direct treatment costs, and QALYs identified rTMS as the dominant therapy compared to antidepressant medications (i.e., lower costs with better outcomes) in all age ranges, with costs/improved QALYs ranging from $2,952/0.32 (older patients) to $11,140/0.43 (younger patients). One-way sensitivity analysis demonstrated that the model was most sensitive to the input variables of cost per rTMS session, monthly prescription drug cost, and the number of rTMS sessions per year. Conclusion rTMS was identified as the dominant therapy compared to antidepressant medication trials over the life of the patient across the lifespan of adults with MDD, given current costs of treatment. These models support the use of rTMS after a single failed antidepressant medication trial versus further attempts at medication treatment in adults with MDD. PMID:29073256

Optimal Location through Distributed Algorithm to Avoid Energy Hole in Mobile Sink WSNs

PubMed Central

Qing-hua, Li; Wei-hua, Gui; Zhi-gang, Chen

2014-01-01

In multihop data collection sensor network, nodes near the sink need to relay on remote data and, thus, have much faster energy dissipation rate and suffer from premature death. This phenomenon causes energy hole near the sink, seriously damaging the network performance. In this paper, we first compute energy consumption of each node when sink is set at any point in the network through theoretical analysis; then we propose an online distributed algorithm, which can adjust sink position based on the actual energy consumption of each node adaptively to get the actual maximum lifetime. Theoretical analysis and experimental results show that the proposed algorithms significantly improve the lifetime of wireless sensor network. It lowers the network residual energy by more than 30% when it is dead. Moreover, the cost for moving the sink is relatively smaller. PMID:24895668

The effect of age at first calving and calving interval on productive life and lifetime profit in korean holsteins.

PubMed

Do, Changhee; Wasana, Nidarshani; Cho, Kwanghyun; Choi, Yunho; Choi, Taejeong; Park, Byungho; Lee, Donghee

2013-11-01

This study was performed to estimate the effect of age at first calving and first two calving intervals on productive life and life time profit in Korean Holsteins. Reproduction data of Korean Holsteins born from 1998 to 2004 and lactation data from 276,573 cows with birth and last dry date that calved between 2000 and 2010 were used for the analysis. Lifetime profit increased with the days of life span. Regression of Life Span on Lifetime profit indicated that there was an increase of 3,800 Won (approximately $3.45) of lifetime profit per day increase in life span. This is evidence that care of each cow is necessary to improve net return and important for farms maintaining profitable cows. The estimates of heritability of age at first calving, first two calving intervals, days in milk for lifetime, lifespan, milk income and lifetime profit were 0.111, 0.088, 0.142, 0.140, 0.143, 0.123, and 0.102, respectively. The low heritabilities indicated that the productive life and economical traits include reproductive and productive characteristics. Age at first calving and interval between first and second calving had negative genetic correlation with lifetime profit (-0.080 and -0.265, respectively). Reducing age at first calving and first calving interval had a positive effect on lifetime profit. Lifetime profit increased to approximately 2,600,000 (2,363.6) from 800,000 Won ($727.3) when age at first calving decreased to (22.3 month) from (32.8 month). Results suggested that reproductive traits such as age at first calving and calving interval might affect various economical traits and consequently influenced productive life and profitability of cows. In conclusion, regard of the age at first calving must be taken with the optimum age at first calving for maximum lifetime profit being 22.5 to 23.5 months. Moreover, considering the negative genetic correlation of first calving interval with lifetime profit, it should be reduced against the present trend of increase.

The Effect of Age at First Calving and Calving Interval on Productive Life and Lifetime Profit in Korean Holsteins

PubMed Central

Do, Changhee; Wasana, Nidarshani; Cho, Kwanghyun; Choi, Yunho; Choi, Taejeong; Park, Byungho; Lee, Donghee

2013-01-01

This study was performed to estimate the effect of age at first calving and first two calving intervals on productive life and life time profit in Korean Holsteins. Reproduction data of Korean Holsteins born from 1998 to 2004 and lactation data from 276,573 cows with birth and last dry date that calved between 2000 and 2010 were used for the analysis. Lifetime profit increased with the days of life span. Regression of Life Span on Lifetime profit indicated that there was an increase of 3,800 Won (approximately $3.45) of lifetime profit per day increase in life span. This is evidence that care of each cow is necessary to improve net return and important for farms maintaining profitable cows. The estimates of heritability of age at first calving, first two calving intervals, days in milk for lifetime, lifespan, milk income and lifetime profit were 0.111, 0.088, 0.142, 0.140, 0.143, 0.123, and 0.102, respectively. The low heritabilities indicated that the productive life and economical traits include reproductive and productive characteristics. Age at first calving and interval between first and second calving had negative genetic correlation with lifetime profit (−0.080 and −0.265, respectively). Reducing age at first calving and first calving interval had a positive effect on lifetime profit. Lifetime profit increased to approximately 2,600,000 (2,363.6) from 800,000 Won ($727.3) when age at first calving decreased to (22.3 month) from (32.8 month). Results suggested that reproductive traits such as age at first calving and calving interval might affect various economical traits and consequently influenced productive life and profitability of cows. In conclusion, regard of the age at first calving must be taken with the optimum age at first calving for maximum lifetime profit being 22.5 to 23.5 months. Moreover, considering the negative genetic correlation of first calving interval with lifetime profit, it should be reduced against the present trend of increase. PMID:25049735

Use of Groundwater Lifetime Expectancy for the Performance Assessment of Deep Geologic Radioactive Waste Repositories.

NASA Astrophysics Data System (ADS)

Cornaton, F.; Park, Y.; Normani, S.; Sudicky, E.; Sykes, J.

2005-12-01

Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, the safety of the host repository depends on two main barriers: the engineered barrier and the natural geological barrier. If radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from the repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. In a second step, the risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The proposed methodology is applied in the context of a typical Canadian Shield environment. Based on a statistically-generated three-dimension network of fracture zones embedded in the granitic host rock, the sensitivity and the uncertainty of lifetime expectancy to the hydraulic and dispersive properties of the fracture network, including the impact of conditioning via their surface expressions, is computed in order to demonstrate the utility of the methodology.

New measurements from fully reconstructed hadronic final states of the $$B^0_2$$ meson at CDF II experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Da Ronco, Saverio

2006-01-01

This thesis reports the reconstruction and lifetime measurement of B +, Bmore » $$0/atop{d}$$ and B$$0/atop{s}$$ mesons, performed using fully reconstructed hadronic decays collected by a dedicated trigger at CDF II experiment. This dedicated trigger selects significantly displaced tracks from primary vertex of p$$\\bar{p}$$ collisions generated at Tevatron collider, obtaining, in this way, huge data samples enriched of long-lived particles, and is therefore suitable for reconstruction of B meson in hadronic decay modes. Due to the trigger track impact parameter selections, the proper decay time distributions of the B mesons no longer follow a simply exponential decay law. This complicates the lifetime measurement and requires a correct understanding and treatment of all the involved effects to keep systematic uncertainties under control. This thesis presents a method to extract the lifetime of B mesons in “ct- biased” samples, based on a Monte Carlo approach, to correct for the effects of the trigger and analysis selections. We present the results of this method when applied on fully re- constructed decays of B collected by CDF II in the data taking runs up to August 2004, corresponding to an integrated luminosity of about 360 pb -1. The lifetimes are extracted using the decay modes B + → $$\\bar{D}$$ 0π +,B$$0\\atop{d}$$ → D -π +, B$$0\\atop{d}$$ → D -π +π -π +, B$$0\\atop{s}$$ → D$$-\\atop{s}$$π + and B$$0\\atop{s}$$ → D$$-\\atop{s}$$ π +π -π +(and c.c.) and performing combined mass-lifetime unbinned maximum likelihood fits.« less

Electronic properties of light-induced recombination centers in boron-doped Czochralski silicon

NASA Astrophysics Data System (ADS)

Schmidt, Jan; Cuevas, Andrés

1999-09-01

In order to study the electronic properties of the recombination centers responsible for the light-induced carrier lifetime degradation commonly observed in high-purity boron-doped Czochralski (Cz) silicon, injection-level dependent carrier lifetime measurements are performed on a large number of boron-doped p-type Cz silicon wafers of various resistivities (1-31 Ω cm) prior to and after light degradation. The measurement technique used is the contactless quasi-steady-state photoconductance method, allowing carrier lifetime measurements over a very broad injection range between 1012 and 1017cm-3. To eliminate all recombination channels not related to the degradation effect, the difference of the inverse lifetimes measured after and before light degradation is evaluated. A detailed analysis of the injection level dependence of the carrier lifetime change using the Shockley-Read-Hall theory shows that the fundamental recombination center created during illumination has an energy level between Ev+0.35 and Ec-0.45 eV and an electron/hole capture time constant ratio between 0.1 and 0.2. This deep-level center is observed in all samples and is attributed to a new type of boron-oxygen complex. Besides this fundamental defect, in some samples an additional shallow-level recombination center at 0.15 eV below Ec or above Ev is found to be activated during light exposure. This second center dominates the light-degraded carrier lifetime only under high-injection conditions and is hence only of minor importance for low-injection operated devices.

Fluorescence lifetime evaluation of whole soils from the Amazon rainforest.

PubMed

Nicolodelli, Gustavo; Tadini, Amanda Maria; Nogueira, Marcelo Saito; Pratavieira, Sebastião; Mounier, Stephane; Huaman, Jose Luis Clabel; Dos Santos, Cléber Hilário; Montes, Célia Regina; Milori, Débora Marcondes Bastos Pereira

2017-08-20

Time-resolved fluorescence spectroscopy (TRFS) is a new tool that can be used to investigate processes of interaction between metal ions and organic matter (OM) in soils, providing a specific analysis of the structure and dynamics of macromolecules. To the best of our knowledge, there are no studies in the literature reporting the use of this technique applied to whole/non-fractionated soil samples, making it a potential method for use in future studies. This work describes the use of TRFS to evaluate the fluorescence lifetimes of OM of whole soils from the Amazon region. Analysis was made of pellets of soils from an oxisol-spodosol system, collected in São Gabriel da Cachoeira (Amazonas, Brazil). The fluorescence lifetimes in the oxisol-spodosol system were attributed to two different fluorophores. One was related to complexation of an OM fraction with metals, resulting in a shorter fluorophore lifetime. A short fluorescence lifetime (2-12 ns) could be associated with simpler structures of the OM, while a long lifetime (19-66 ns) was associated with more complex OM structures. This new TRFS technique for analysis of the fluorescence lifetime in whole soil samples complies with the principles of green chemistry.

Associations between strain, herd size, age at first calving, culling reason and lifetime performance characteristics in Holstein-Friesian cows.

PubMed

Adamczyk, K; Makulska, J; Jagusiak, W; Węglarz, A

2017-02-01

Cow longevity and lifetime performance traits are good indicators of breeding effectiveness and animal welfare. They are also interrelated with the economics of dairy herd. Unfortunately, a high milk yield is often associated with deteriorated cow health and fertility and, consequently, with an increased culling rate. This situation, observed also in the Polish population of Holstein-Friesian cattle, inspired us to undertake a study on the associations between some factors and lifetime performance characteristics. The data set consisted of the records on 135 496 cows, including 131 526 of the Black and White strain (BW), and 3970 of the Red and White strain (RW) covered by performance recording and culled in 2012. It was found that cows of the BW strain and those from the largest herds (>100 cows) reached higher lifetime and mean daily energy-corrected milk (ECM) yields than cows of the RW strain and those from smaller herds culled at a similar age. Cows youngest at first calving (<2.0 years) were characterised by the highest lifetime ECM yield. It indicates that heifers can be bred even when they are younger than 15 to 16 months with no significant negative effect on their later performance. Infertility and reproduction problems (39.6%) and udder diseases (15.5%) constituted the most frequent reasons for cow culling. Cow longevity and lifetime productivity were considerably affected by the interactions between the studied factors.

Battery Lifetime Analysis and Simulation Tool Suite | Transportation

Science.gov Websites

comparisons of different battery-use strategies to predict long-term performance in electric vehicle (EV) and economic and greenhouse gas impacts of different EV scenarios. An illustrated graphic showing thermal . Users can enter their own battery duty cycles for direct simulation to evaluate the impacts of different

Violent Self-Harm in Schizophrenia

ERIC Educational Resources Information Center

Symonds, Catherine S.; Taylor, Steve; Tippins, Val; Turkington, Douglas

2006-01-01

Patients with schizophrenia have a substantial lifetime suicide risk, especially by violent means. Little published work exists on self-harm (SH) in this population. The goal of this study was to examine whether patients with schizophrenia were also more likely to self-harm in a violent manner. A retrospective analysis performed on method, motive,…

Impact of Perceived Risk and Friend Influence on Alcohol and Marijuana Use among Students

ERIC Educational Resources Information Center

Merianos, Ashley L.; Rosen, Brittany L.; Montgomery, LaTrice; Barry, Adam E.; Smith, Matthew Lee

2017-01-01

We performed a secondary analysis of Adolescent Health Risk Behavior Survey data (N=937), examining associations between lifetime alcohol and marijuana use with intrapersonal (i.e., risk perceptions) and interpersonal (e.g., peer approval and behavior) factors. Multinomial and binary logistic regression analyses contend students reporting lifetime…

International Space Station Cathode Life Testing

NASA Technical Reports Server (NTRS)

Soulas, George C.; Sarver-Verhey, Timothy R.

1997-01-01

Four hollow cathode assembly (HCA) life tests were initiated at operating conditions simulating on-orbit operation of the International Space Station plasma contactor. The objective of these tests is to demonstrate the mission-required 18,000 hour lifetime with high-fidelity development model HCAS. HCAs are operated with a continuous 6 sccm xenon flow rate and 3 A anode current. On-orbit emission current requirements are simulated with a square waveform consisting of 50 minutes at a 2.5 A emission current and 40 minutes with no emission current. One HCA test was terminated after approximately 8,000 hours so that a destructive analysis could be performed. The analysis revealed no life-limiting processes and the ultimate lifetime was projected to be greater than the mission requirement. Testing continues for the remaining three HCAs which have accumulated approximately 8,000 hours, 10,000 hours, and 11,000 hours, respectively, as of June 1997. Anode and bias voltages, strong indicators of cathode electron emitter condition, are within acceptable ranges and have exhibited no life- or performance-limiting phenomena to date.

Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices.

PubMed

Li, Zhigang; Liu, Boying; Yuan, Mengxiong; Zhang, Feifei; Guo, Jiaqiang

2016-01-01

Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information.

Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices

PubMed Central

Li, Zhigang; Liu, Boying; Yuan, Mengxiong; Zhang, Feifei; Guo, Jiaqiang

2016-01-01

Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information. PMID:27907188

High Voltage Insulation Technology

NASA Astrophysics Data System (ADS)

Scherb, V.; Rogalla, K.; Gollor, M.

2008-09-01

In preparation of new Electronic Power Conditioners (EPC's) for Travelling Wave Tub Amplifiers (TWTA's) on telecom satellites a study for the development of new high voltage insulation technology is performed. The initiative is mandatory to allow compact designs and to enable higher operating voltages. In a first task a market analysis was performed, comparing different materials with respect to their properties and processes. A hierarchy of selection criteria was established and finally five material candidates (4 Epoxy resins and 1 Polyurethane resin) were selected to be further investigated in the test program. Samples for the test program were designed to represent core elements of an EPC, the high voltage transformer and Printed Circuit Boards of the high voltage section. All five materials were assessed in the practical work flow of the potting process and electrical, mechanical, thermal and lifetime testing was performed. Although the lifetime tests results were overlayed by a larges scatter, finally two candidates have been identified for use in a subsequent qualification program. This activity forms part of element 5 of the ESA ARTES Programme.

Projected lifetime risks and hospital care expenditure for traumatic injury.

PubMed

Chang, David C; Anderson, Jamie E; Kobayashi, Leslie; Coimbra, Raul; Bickler, Stephen W

2012-08-01

The lifetime risk and expected cost of trauma care would be valuable for health policy planners, but this information is currently unavailable. The cumulative incidence rates methodology, based on a cross-sectional population analysis, offers an alternative approach to prohibitively costly prospective cohort studies. Retrospective analysis of the California Office of Statewide Health Planning and Development (OSHPD) database was performed for 2008. Trauma admissions were identified by ICD-9 primary diagnosis codes 800-959, with certain exclusions. Cumulative incidence rates were calculated as the cumulative summation of incidence risks sequentially across age groups. A total of 2.2 million admissions were identified, with mean age of 63.8 y, 49.6% men, 82.8% Whites, 5.7% Blacks, 11.3% Hispanics, and 3.1% Asians. The cumulative incidence rate for patients older than age 85 y was 1119 per 10,000 people, with the majority of risk in the elderly, compared with 24,325 per 10,000 people for all-cause hospitalizations. The rates were 946 for men, 1079 for women, 999 for non-Hispanic Whites, 568 for Blacks, 577 for Hispanics, and 395 for Asians, per 10,000 population. The cumulative expected hospital charge was $6538, compared with $81,257 for all-cause hospitalizations. The cumulative lifetime risk of trauma/injury requiring hospitalization for a person living to age 85 y in California is 11.2%, accounting for 4.6% of expected lifetime hospitalizations, but accounting for 8.0% of expected lifetime hospital expenditures. Risk of trauma is significant in the elderly. The total expenditure for all trauma hospitalizations in California was $7.62 billion in 2008. Copyright © 2012 Elsevier Inc. All rights reserved.

Lifetime shift work exposure: association with anthropometry, body composition, blood pressure, glucose and heart rate variability.

PubMed

Souza, Breno Bernardes; Monteze, Nayara Mussi; de Oliveira, Fernando Luiz Pereira; de Oliveira, José Magalhães; de Freitas Nascimento, Silvia; Marques do Nascimento Neto, Raimundo; Sales, Maria Lilian; Souza, Gabriela Guerra Leal

2015-03-01

To evaluate the association between lifetime exposure to shift work and blood pressure, fasting glucose (FG), anthropometric variables, body composition and heart rate variability (HRV). Male shift workers (N=438) were evaluated using principal component (PC) analysis. The variables used were: weight, body mass index (BMI), waist circumference (WC), neck circumference (NC), hip circumference (HC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat mass (BFKg), body fat percentage (BF%), visceral fat area (VFA), FG, systolic (SBP) and diastolic blood pressure (DBP), and HRV variables. ECG was performed, extracting heart rate (HR), root mean square of the successive differences (RMSSD), high frequency (HF), low frequency (LF) and the LF/HF ratio. Using linear regression models, the lifetime shift work exposure was associated with each PC. Five PCs were obtained, which accounted for 79.6% of the total variation of the data. PC1 (weight, BMI, WC, NC, HC, WHR, WHtR, BFKg, BF% and VFA) was designated as body obesity; PC2 (HF, RMSSD and LF) as good cardiac regulation; PC3 (SBP and DBP) as blood pressure; PC4 (LF/HF ratio and HR) as bad cardiac regulation and PC5 (WHR and FG) as insulin resistance. After age adjustment, the regression analysis showed that lifetime shift work was negatively associated with PC2 and positively associated with PC3. The association of lifetime shift work exposure with PC2 and PC3 suggests that shift work promotes unfavourable changes in autonomic cardiac control related to a decrease in parasympathetic modulation and an increase in blood pressure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Damage modeling and statistical analysis of optics damage performance in MJ-class laser systems.

PubMed

Liao, Zhi M; Raymond, B; Gaylord, J; Fallejo, R; Bude, J; Wegner, P

2014-11-17

Modeling the lifetime of a fused silica optic is described for a multiple beam, MJ-class laser system. This entails combining optic processing data along with laser shot data to account for complete history of optic processing and shot exposure. Integrating with online inspection data allows for the construction of a performance metric to describe how an optic performs with respect to the model. This methodology helps to validate the damage model as well as allows strategic planning and identifying potential hidden parameters that are affecting the optic's performance.

Cross Layer Design for Optimizing Transmission Reliability, Energy Efficiency, and Lifetime in Body Sensor Networks.

PubMed

Chen, Xi; Xu, Yixuan; Liu, Anfeng

2017-04-19

High transmission reliability, energy efficiency, and long lifetime are pivotal issues for wireless body area networks (WBANs. However, these performance metrics are not independent of each other, making it hard to obtain overall improvements through optimizing one single aspect. Therefore, a Cross Layer Design Optimal (CLDO) scheme is proposed to simultaneously optimize transmission reliability, energy efficiency, and lifetime of WBANs from several layers. Firstly, due to the fact that the transmission power of nodes directly influences the reliability of links, the optimized transmission power of different nodes is deduced, which is able to maximize energy efficiency in theory under the premise that requirements on delay and jitter are fulfilled. Secondly, a relay decision algorithm is proposed to choose optimized relay nodes. Using this algorithm, nodes will choose relay nodes that ensure a balance of network energy consumption, provided that all nodes transmit with optimized transmission power and the same packet size. Thirdly, the energy consumption of nodes is still unbalanced even with optimized transmission power because of their different locations in the topology of the network. In addition, packet size also has an impact on final performance metrics. Therefore, a synthesized cross layer method for optimization is proposed. With this method, the transmission power of nodes with more residual energy will be enhanced while suitable packet size is determined for different links in the network, leading to further improvements in the WBAN system. Both our comprehensive theoretical analysis and experimental results indicate that the performance of our proposed scheme is better than reported in previous studies. Relative to the relay selection and power control game (RSPCG) scheme, the CLDO scheme can enhance transmission reliability by more than 44.6% and prolong the lifetime by as much as 33.2%.

Cross Layer Design for Optimizing Transmission Reliability, Energy Efficiency, and Lifetime in Body Sensor Networks

PubMed Central

Chen, Xi; Xu, Yixuan; Liu, Anfeng

2017-01-01

High transmission reliability, energy efficiency, and long lifetime are pivotal issues for wireless body area networks (WBANs). However, these performance metrics are not independent of each other, making it hard to obtain overall improvements through optimizing one single aspect. Therefore, a Cross Layer Design Optimal (CLDO) scheme is proposed to simultaneously optimize transmission reliability, energy efficiency, and lifetime of WBANs from several layers. Firstly, due to the fact that the transmission power of nodes directly influences the reliability of links, the optimized transmission power of different nodes is deduced, which is able to maximize energy efficiency in theory under the premise that requirements on delay and jitter are fulfilled. Secondly, a relay decision algorithm is proposed to choose optimized relay nodes. Using this algorithm, nodes will choose relay nodes that ensure a balance of network energy consumption, provided that all nodes transmit with optimized transmission power and the same packet size. Thirdly, the energy consumption of nodes is still unbalanced even with optimized transmission power because of their different locations in the topology of the network. In addition, packet size also has an impact on final performance metrics. Therefore, a synthesized cross layer method for optimization is proposed. With this method, the transmission power of nodes with more residual energy will be enhanced while suitable packet size is determined for different links in the network, leading to further improvements in the WBAN system. Both our comprehensive theoretical analysis and experimental results indicate that the performance of our proposed scheme is better than reported in previous studies. Relative to the relay selection and power control game (RSPCG) scheme, the CLDO scheme can enhance transmission reliability by more than 44.6% and prolong the lifetime by as much as 33.2%. PMID:28422062

US/UK second level panel discussions on the health and value of: Ageing and lifetime predictions (u)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castro, Richard G

2011-01-18

Many healthy physics, engineering, and materials exchanges are being accomplished in ageing and lifetime prediction that directly supports US and UK Stockpile Management Programs. Lifetime assessment studies of silicon foams under compression - Joint AWE/LANLlLLNL study of compression set in stress cushions completed. Provides phenomenological prediction out to 50 years. Polymer volatile out-gassing studies - New exchange on the out-gassing of Ethylene Vinyl Acetate (EVA) using isotopic {sup 13}C labeling studies to interrogate mechanistic processes. Infra-red (IR) gas cell analytical capabilities developed by AWE will be used to monitor polymer out-gassing profiles. Pu Strength ageing Experiments and Constitutive Modeling -more » In recently compared modeling strategies for ageing effects on Pu yield strength at high strain rates, a US/UK consensus was reached on the general principle that the ageing effect is additive and not multiplicative. The fundamental mechanisms for age-strengthening in Pu remains unknown. Pu Surface and Interface Reactions - (1) US/UK secondment resulted in developing a metal-metal oxide model for radiation damaged studies consistent with a Modified Embedded Atom Method (MEAM) potential; and (2) Joint US/UK collaboration to study the role of impurities in hydride initiation. Detonator Ageing (wide range of activities) - (1) Long-term ageing study with field trials at Pantex incorporating materials from LANL, LLNL, SNL and AWE; (2) Characterization of PETN growth to detonation process; (3) Detonator performance modeling; and (4) Performance fault tree analysis. Benefits are a unified approach to lifetime prediction that Includes: materials characterization and the development of ageing models through improved understanding of the relationship between materials properties, ageing properties and detonator performance.« less

High resolution multiplexed functional imaging in live embryos (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xu, Dongli; Zhou, Weibin; Peng, Leilei

2017-02-01

Fourier multiplexed fluorescence lifetime imaging (FmFLIM) scanning laser optical tomography (FmFLIM-SLOT) combines FmFLIM and Scanning laser optical tomography (SLOT) to perform multiplexed 3D FLIM imaging of live embryos. The system had demonstrate multiplexed functional imaging of zebrafish embryos genetically express Foster Resonant Energy Transfer (FRET) sensors. However, previous system has a 20 micron resolution because the focused Gaussian beam diverges quickly from the focused plane, makes it difficult to achieve high resolution imaging over a long projection depth. Here, we present a high-resolution FmFLIM-SLOT system with achromatic Bessel beam, which achieves 3 micron resolution in 3D deep tissue imaging. In Bessel-FmFLIM-SLOT, multiple laser excitation lines are firstly intensity modulated by a Michelson interferometer with a spinning polygon mirror optical delay line, which enables Fourier multiplexed multi-channel lifetime measurements. Then, a spatial light modulator and a prism are used to transform the modulated Gaussian laser beam to an achromatic Bessel beam. The achromatic Bessel beam scans across the whole specimen with equal angular intervals as sample rotated. After tomography reconstruction and the frequency domain lifetime analysis method, both the 3D intensity and lifetime image of multiple excitation-emission can be obtained. Using Bessel-FmFLIM-SLOT system, we performed cellular-resolution FLIM tomography imaging of live zebrafish embryo. Genetically expressed FRET sensors in these embryo will allow non-invasive observation of multiple biochemical processes in vivo.

FLIMX: A Software Package to Determine and Analyze the Fluorescence Lifetime in Time-Resolved Fluorescence Data from the Human Eye

PubMed Central

Klemm, Matthias; Schweitzer, Dietrich; Peters, Sven; Sauer, Lydia; Hammer, Martin; Haueisen, Jens

2015-01-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique for measuring the in vivo autofluorescence intensity decays generated by endogenous fluorophores in the ocular fundus. Here, we present a software package called FLIM eXplorer (FLIMX) for analyzing FLIO data. Specifically, we introduce a new adaptive binning approach as an optimal tradeoff between the spatial resolution and the number of photons required per pixel. We also expand existing decay models (multi-exponential, stretched exponential, spectral global analysis, incomplete decay) to account for the layered structure of the eye and present a method to correct for the influence of the crystalline lens fluorescence on the retina fluorescence. Subsequently, the Holm-Bonferroni method is applied to FLIO measurements to allow for group comparisons between patients and controls on the basis of fluorescence lifetime parameters. The performance of the new approaches was evaluated in five experiments. Specifically, we evaluated static and adaptive binning in a diabetes mellitus patient, we compared the different decay models in a healthy volunteer and performed a group comparison between diabetes patients and controls. An overview of the visualization capabilities and a comparison of static and adaptive binning is shown for a patient with macular hole. FLIMX’s applicability to fluorescence lifetime imaging microscopy is shown in the ganglion cell layer of a porcine retina sample, obtained by a laser scanning microscope using two-photon excitation. PMID:26192624

Stochastic Analysis of Orbital Lifetimes of Spacecraft

NASA Technical Reports Server (NTRS)

Sasamoto, Washito; Goodliff, Kandyce; Cornelius, David

2008-01-01

A document discusses (1) a Monte-Carlo-based methodology for probabilistic prediction and analysis of orbital lifetimes of spacecraft and (2) Orbital Lifetime Monte Carlo (OLMC)--a Fortran computer program, consisting of a previously developed long-term orbit-propagator integrated with a Monte Carlo engine. OLMC enables modeling of variances of key physical parameters that affect orbital lifetimes through the use of probability distributions. These parameters include altitude, speed, and flight-path angle at insertion into orbit; solar flux; and launch delays. The products of OLMC are predicted lifetimes (durations above specified minimum altitudes) for the number of user-specified cases. Histograms generated from such predictions can be used to determine the probabilities that spacecraft will satisfy lifetime requirements. The document discusses uncertainties that affect modeling of orbital lifetimes. Issues of repeatability, smoothness of distributions, and code run time are considered for the purpose of establishing values of code-specific parameters and number of Monte Carlo runs. Results from test cases are interpreted as demonstrating that solar-flux predictions are primary sources of variations in predicted lifetimes. Therefore, it is concluded, multiple sets of predictions should be utilized to fully characterize the lifetime range of a spacecraft.

Genetic selection for lifetime reproductive performance.

PubMed

Clutter, A C

2009-01-01

Genetic improvement of sow lifetime reproductive performance has value from both the economic perspectives of pork producers and the pork industry, but also from the perspective of ethical and animal welfare concerns by the general public. Genetic potential for piglets produced from individual litters is a primary determinant of lifetime prolificacy, but females must be able to sustain productivity without injury or death beyond the achievement of positive net present value. Evidence exists for between- and within-line genetic variation in sow lifetime performance, suggesting that improvements may be made by both line choices and genetic selection within lines. However, some of the same barriers to accurate within-line selection that apply to individual litter traits also present challenges to genetic selection for sow lifetime prolificacy: generally low heritabilites, sex-limited expression, expression after the age that animals are typically selected, and unfavorable genetic correlations with other traits in the profit function. In addition, there is an inherent conflict within the genetic nucleus herds where selections take place between the goal of shortened generation interval to accelerate genetic progress and the expression of sow lifetime traits. A proliferation in the industry of commercial multipliers with direct genetic ties and routine record flows to genetic nucleus herds provides a framework for accurate estimates of relevant genetic variances and covariances, and estimation of breeding values for sow lifetime traits that can be used in genetic selection.

Lifetime assessment analysis of Galileo Li/SO2 cells: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levy, S.C.; Jaeger, C.D.; Bouchard, D.A.

Galileo Li/SO2 cells from five lots and five storage temperatures were studied to establish a database from which the performance of flight modules may be predicted. Nondestructive tests consisting of complex impedance analysis and a 15-s pulse were performed on all cells. Chemical analysis was performed on one cell from each lot/storage group, and the remaining cells were discharged at Galileo mission loads. An additional number of cells were placed on high-temperature accelerated aging storage for 6 months and then discharged. All data were statistically analyzed. Results indicate that the present Galileo design Li/SO2 cell will satisfy electrical requirements formore » a 10-year mission. 10 figs., 4 tabs.« less

Cost-effectiveness of left ventricular assist devices for patients with end-stage heart failure: analysis of the French hospital discharge database.

PubMed

Tadmouri, Abir; Blomkvist, Josefin; Landais, Cécile; Seymour, Jerome; Azmoun, Alexandre

2018-02-01

Although left ventricular assist devices (LVADs) are currently approved for coverage and reimbursement in France, no French cost-effectiveness (CE) data are available to support this decision. This study aimed at estimating the CE of LVAD compared with medical management in the French health system. Individual patient data from the 'French hospital discharge database' (Medicalization of information systems program) were analysed using Kaplan-Meier method. Outcomes were time to death, time to heart transplantation (HTx), and time to death after HTx. A micro-costing method was used to calculate the monthly costs extracted from the Program for the Medicalization of Information Systems. A multistate Markov monthly cycle model was developed to assess CE. The analysis over a lifetime horizon was performed from the perspective of the French healthcare payer; discount rates were 4%. Probabilistic and deterministic sensitivity analyses were performed. Outcomes were quality-adjusted life years (QALYs) and incremental CE ratio (ICER). Mean QALY for an LVAD patient was 1.5 at a lifetime cost of €190 739, delivering a probabilistic ICER of €125 580/QALY [95% confidence interval: 105 587 to 150 314]. The sensitivity analysis showed that the ICER was mainly sensitive to two factors: (i) the high acquisition cost of the device and (ii) the device performance in terms of patient survival. Our economic evaluation showed that the use of LVAD in patients with end-stage heart failure yields greater benefit in terms of survival than medical management at an extra lifetime cost exceeding the €100 000/QALY. Technological advances and device costs reduction shall hence lead to an improvement in overall CE. © 2017 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

Cost-Effectiveness of Sensor-Augmented Pump Therapy with Low Glucose Suspend Versus Standard Insulin Pump Therapy in Two Different Patient Populations with Type 1 Diabetes in France.

PubMed

Roze, Stéphane; Smith-Palmer, Jayne; Valentine, William; Payet, Vincent; de Portu, Simona; Papo, Natalie; Cucherat, Michel; Hanaire, Helene

2016-02-01

Sensor-augmented pump therapy (SAP) provides a useful adjunct relative to continuous subcutaneous insulin infusion (CSII) alone. It can provide early warning of the onset of hyperglycemia and hypoglycemia and has the functionality to suspend insulin delivery if sensor glucose levels fall below a predefined threshold. The aim was to assess the cost-effectiveness of SAP with low glucose suspend (LGS) versus CSII alone in type 1 diabetes. Cost-effectiveness analysis was performed using the CORE Diabetes Model, using published clinical input data. The analysis was performed in two cohorts: one with uncontrolled glycated hemoglobin at baseline and one at elevated risk for hypoglycemic events. The analysis was conducted from a healthcare payer perspective over a lifetime time horizon; future costs and clinical outcomes were discounted at 4% per annum. In patients with uncontrolled glycated hemoglobin at baseline, SAP + LGS resulted in improved discounted quality-adjusted life expectancy (QALE) versus CSII (10.55 quality-adjusted life-years [QALYs] vs. 9.36 QALYs) but higher mean lifetime direct costs (€84,972 vs. €49,171) resulting in an incremental cost-effectiveness ratio (ICER) of €30,163 per QALY gained. In patients at elevated risk for hypoglycemia, the ICER was €22,005 per QALY gained for SAP + LGS versus CSII as lifetime costs were higher (€88,680 vs. €57,097), but QALE was also higher (18.46 QALYs vs. 18.30 QALYs). In France, projected improvements in outcomes with SAP + LGS versus CSII translated into an ICER generally considered as good value for money, particularly in patients who experience frequent and/or problematic hypoglycemic events.

Cost-Effectiveness Analysis of the Self-Management Program for Thai Patients with Metabolic Syndrome.

PubMed

Sakulsupsiri, Anut; Sakthong, Phantipa; Winit-Watjana, Win

2016-05-01

Lifestyle modification programs are partly evaluated for their usefulness. This study aimed to assess the cost-effectiveness and healthy lifestyle persistence of a self-management program (SMP) for patients with metabolic syndrome (MetS) in Thai health care settings. A cost-effectiveness analysis was performed on the basis of an intervention study of 90 patients with MetS randomly allocated to the SMP and control groups. A Markov model with the Difference-in-Difference method was used to predict the lifetime costs from a societal perspective and quality-adjusted life-years (QALYs), of which 95% confidence intervals (CIs) were estimated by bootstrapping. The cost-effectiveness analysis, along with healthy lifestyle persistence, was performed using the discount rate of 3% per annum. Parameter uncertainties were identified using one-way and probabilistic sensitivity analyses. The lifetime costs tended to decrease in both groups. The SMP could save lifetime costs (-2310 baht; 95% CI -5960 to 1400) and gain QALYs (0.0098; 95% CI -0.0003 to 0.0190), compared with ordinary care. The probability of cost-effectiveness was 99.4% from the Monte-Carlo simulation, and the program was deemed cost-effective at dropout rates below 69% per year as determined by the threshold of 160,000 baht per QALY gained. The cost of macrovascular complications was the most influencing variable for the overall incremental cost-effectiveness ratio. The SMP provided by the health care settings is marginally cost-effective, and the persistence results support the implementation of the program to minimize the complications and economic burden of patients with MetS. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Nondestructive assessment of collagen hydrogel cross-linking using time-resolved autofluorescence imaging

NASA Astrophysics Data System (ADS)

Sherlock, Benjamin E.; Harvestine, Jenna N.; Mitra, Debika; Haudenschild, Anne; Hu, Jerry; Athanasiou, Kyriacos A.; Leach, J. Kent; Marcu, Laura

2018-03-01

We investigate the use of a fiber-based, multispectral fluorescence lifetime imaging (FLIm) system to nondestructively monitor changes in mechanical properties of collagen hydrogels caused by controlled application of widely used cross-linking agents, glutaraldehyde (GTA) and ribose. Postcross-linking, fluorescence lifetime images are acquired prior to the hydrogels being processed by rheological or tensile testing to directly probe gel mechanical properties. To preserve the sterility of the ribose-treated gels, FLIm is performed inside a biosafety cabinet (BSC). A pairwise correlation analysis is used to quantify the relationship between mean hydrogel fluorescence lifetimes and the storage or Young's moduli of the gels. In the GTA study, we observe strong and specific correlations between fluorescence lifetime and the storage and Young's moduli. Similar correlations are not observed in the ribose study and we postulate a reason for this. Finally, we demonstrate the ability of FLIm to longitudinally monitor dynamic cross-link formation. The strength of the GTA correlations and deployment of our fiber-based FLIm system inside the aseptic environment of a BSC suggests that this technique may be a valuable tool for the tissue engineering community where longitudinal assessment of tissue construct maturation in vitro is highly desirable.

Development of Precise Lunar Orbit Propagator and Lunar Polar Orbiter's Lifetime Analysis

NASA Astrophysics Data System (ADS)

Song, Young-Joo; Park, Sang-Young; Kim, Hae-Dong; Sim, Eun-Sup

2010-06-01

To prepare for a Korean lunar orbiter mission, a precise lunar orbit propagator; Yonsei precise lunar orbit propagator (YSPLOP) is developed. In the propagator, accelerations due to the Moon's non-spherical gravity, the point masses of the Earth, Moon, Sun, Mars, Jupiter and also, solar radiation pressures can be included. The developed propagator's performance is validated and propagation errors between YSPOLP and STK/Astrogator are found to have about maximum 4-m, in along-track direction during 30 days (Earth's time) of propagation. Also, it is found that the lifetime of a lunar polar orbiter is strongly affected by the different degrees and orders of the lunar gravity model, by a third body's gravitational attractions (especially the Earth), and by the different orbital inclinations. The reliable lifetime of circular lunar polar orbiter at about 100 km altitude is estimated to have about 160 days (Earth's time). However, to estimate the reasonable lifetime of circular lunar polar orbiter at about 100 km altitude, it is strongly recommended to consider at least 50 × 50 degrees and orders of the lunar gravity field. The results provided in this paper are expected to make further progress in the design fields of Korea's lunar orbiter missions.

Scaling of Ion Thrusters to Low Power

NASA Technical Reports Server (NTRS)

Patterson, Michael J.; Grisnik, Stanley P.; Soulas, George C.

1998-01-01

Analyses were conducted to examine ion thruster scaling relationships in detail to determine performance limits, and lifetime expectations for thruster input power levels below 0.5 kW. This was motivated by mission analyses indicating the potential advantages of high performance, high specific impulse systems for small spacecraft. The design and development status of a 0.1-0.3 kW prototype small thruster and its components are discussed. Performance goals include thruster efficiencies on the order of 40% to 54% over a specific impulse range of 2000 to 3000 seconds, with a lifetime in excess of 8000 hours at full power. Thruster technologies required to achieve the performance and lifetime targets are identified.

The Economic Impact of Acetabular Labral Tears: A Cost-effectiveness Analysis Comparing Hip Arthroscopic Surgery and Structured Rehabilitation Alone in Patients Without Osteoarthritis.

PubMed

Lodhia, Parth; Gui, Chengcheng; Chandrasekaran, Sivashankar; Suarez-Ahedo, Carlos; Dirschl, Douglas R; Domb, Benjamin G

2016-07-01

Hip arthroscopic surgery has emerged as a successful procedure to manage acetabular labral tears and concurrent hip injuries, which if left untreated, may contribute to hip osteoarthritis (OA). Therefore, it is essential to analyze the economic impact of this treatment option. To investigate the cost-effectiveness of hip arthroscopic surgery versus structured rehabilitation alone for acetabular labral tears, to examine the effects of age on cost-effectiveness, and to estimate the rate of symptomatic OA and total hip arthroplasty (THA) in both treatment arms over a lifetime horizon. Economic and decision analysis; Level of evidence, 2. A cost-effectiveness analysis of hip arthroscopic surgery compared with structured rehabilitation for symptomatic labral tears was performed using a Markov decision model constructed over a lifetime horizon. It was assumed that patients did not have OA. Direct costs (in 2014 United States dollars), utilities of health states (in quality-adjusted life years [QALYs] gained), and probabilities of transitioning between health states were estimated from a comprehensive literature review. Costs were estimated using national averages of Medicare reimbursements, adjusted for all payers in the United States from a societal perspective. Utilities were estimated from the Harris Hip Score. Cost-effectiveness was assessed using the incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses were performed to determine the effect of uncertainty on the model outcomes. For a cohort representative of patients undergoing hip arthroscopic surgery at our facility, arthroscopic surgery was more costly (additional $2653) but generated more utility (additional 3.94 QALYs) compared with rehabilitation over a lifetime. The mean ICER was $754/QALY, well below the conventional willingness to pay of $50,000/QALY. Arthroscopic surgery was cost-effective for 94.5% of patients. Although arthroscopic surgery decreased in cost-effectiveness with increasing age, arthroscopic surgery remained more cost-effective than rehabilitation for patients in the second to seventh decades of life. The lifetime incidence of symptomatic hip OA was over twice as high for patients treated with rehabilitation compared with arthroscopic surgery. The preferred treatment was sensitive to the utility after successful hip arthroscopic surgery, although the utility at which arthroscopic surgery becomes less cost-effective than rehabilitation is far below our best estimate. For older patients, the lifetime cost of arthroscopic surgery was greater, while the lifetime utility of arthroscopic surgery was less, approaching that of the rehabilitation arm. Hip arthroscopic surgery is more cost-effective and results in a considerably lower incidence of symptomatic OA than structured rehabilitation alone in treating symptomatic labral tears of patients in the second to seventh decades of life without pre-existing OA. © 2016 The Author(s).

Analysis of Present Day and Future OH and Methane Lifetime in the ACCMIP Simulations

NASA Technical Reports Server (NTRS)

Voulgarakis, A.; Naik, V.; Lamarque, J. -F.; Shindell, D. T.; Young, P. J.; Prather, M. J.; Wild, O.; Field, R. D.; Bergmann, D.; Cameron-Smith P.;

Fluorescence lifetime microscopy with a time- and space-resolved single-photon counting detector

PubMed Central

Michalet, X.; Siegmund, O.H.W.; Vallerga, J.V.; Jelinsky, P.; Pinaud, F. F.; Millaud, J.E.; Weiss, S.

2017-01-01

We have recently developed a wide-field photon-counting detector (the H33D detector) having high-temporal and high-spatial resolutions and capable of recording up to 500,000 photons per sec. Its temporal performance has been previously characterized using solutions of fluorescent materials with different lifetimes, and its spatial resolution using sub-diffraction objects (beads and quantum dots). Here we show its application to fluorescence lifetime imaging of live cells and compare its performance to a scanning confocal TCSPC approach. With the expected improvements in photocathode sensitivity and increase in detector throughput, this technology appears as a promising alternative to the current lifetime imaging solutions. PMID:29449756

Computing Lives And Reliabilities Of Turboprop Transmissions

NASA Technical Reports Server (NTRS)

Coy, J. J.; Savage, M.; Radil, K. C.; Lewicki, D. G.

1991-01-01

Computer program PSHFT calculates lifetimes of variety of aircraft transmissions. Consists of main program, series of subroutines applying to specific configurations, generic subroutines for analysis of properties of components, subroutines for analysis of system, and common block. Main program selects routines used in analysis and causes them to operate in desired sequence. Series of configuration-specific subroutines put in configuration data, perform force and life analyses for components (with help of generic component-property-analysis subroutines), fill property array, call up system-analysis routines, and finally print out results of analysis for system and components. Written in FORTRAN 77(IV).

Crystallization Kinetics of an Amorphous Pharmaceutical Compound Using Fluorescence-Lifetime-Imaging Microscopy.

PubMed

Rautaniemi, Kaisa; Vuorimaa-Laukkanen, Elina; Strachan, Clare J; Laaksonen, Timo

2018-05-07

Pharmaceutical scientists are increasingly interested in amorphous drug formulations especially because of their higher dissolution rates. Consequently, the thorough characterization and analysis of these formulations are becoming more and more important for the pharmaceutical industry. Here, fluorescence-lifetime-imaging microscopy (FLIM) was used to monitor the crystallization of an amorphous pharmaceutical compound, indomethacin. Initially, we identified different solid indomethacin forms, amorphous and γ- and α-crystalline, on the basis of their time-resolved fluorescence. All of the studied indomethacin forms showed biexponential decays with characteristic fluorescence lifetimes and amplitudes. Using this information, the crystallization of amorphous indomethacin upon storage in 60 °C was monitored for 10 days with FLIM. The progress of crystallization was detected as lifetime changes both in the FLIM images and in the fluorescence-decay curves extracted from the images. The fluorescence-lifetime amplitudes were used for quantitative analysis of the crystallization process. We also demonstrated that the fluorescence-lifetime distribution of the sample changed during crystallization, and when the sample was not moved between measuring times, the lifetime distribution could also be used for the analysis of the reaction kinetics. Our results clearly show that FLIM is a sensitive and nondestructive method for monitoring solid-state transformations on the surfaces of fluorescent samples.

Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 2

NASA Technical Reports Server (NTRS)

1990-01-01

This report summarizes and documents the results of the 12-month phase 1 work effort. The objective of phase 1 was to establish the conceptional definition of the laser atmospheric wind sounder (LAWS) sensor system, including accommodations analyses to ensure compatibility with the Space Station Freedom (SSF) and the Earth Observing System (EOS) Polar Orbiting Platform (POP). Various concepts were investigated with trade studies performed to select the configuration to be carried forward to the phase 2 Preliminary Design Definition. A summary of the LAWS system and subsystem trade studies that were performed leading to the baseline design configuration is presented in the appendix. The overall objective of the LAWS Project is to define, design, and implement an operational space based facility, LAWS, for accurate measurement of Earth wind profiles. Phase 1 addressed three major areas: (1) requirements definition; (2) instrument concepts and configurations; and (3) performance analysis. For the LAWS instrument concepts and configurations, the issues which press the technological state of the art are reliable detector lifetime and laser performance and lifetime. Lag angle compensation, pointing accuracy, satellite navigation, and telescope design are significant technical issues, but they are considered to be currently state of the art. The primary issues for performance analysis concern interaction with the atmosphere in terms of backscatter and attenuation, wind variance, and cloud blockage. The phase 1 tasks were formulated to address these significant technical issues and demonstrate the technical feasibility of the LAWS concept. Primary emphasis was placed on analysis/trade and identification of candidate concepts. Promising configurations were evaluated for performance, sensitivities, risks, and budgetary costs. Lockheed's baseline LAWS configuration is presented.

A 3-Component Mixture of Rayleigh Distributions: Properties and Estimation in Bayesian Framework

PubMed Central

Aslam, Muhammad; Tahir, Muhammad; Hussain, Zawar; Al-Zahrani, Bander

2015-01-01

To study lifetimes of certain engineering processes, a lifetime model which can accommodate the nature of such processes is desired. The mixture models of underlying lifetime distributions are intuitively more appropriate and appealing to model the heterogeneous nature of process as compared to simple models. This paper is about studying a 3-component mixture of the Rayleigh distributionsin Bayesian perspective. The censored sampling environment is considered due to its popularity in reliability theory and survival analysis. The expressions for the Bayes estimators and their posterior risks are derived under different scenarios. In case the case that no or little prior information is available, elicitation of hyperparameters is given. To examine, numerically, the performance of the Bayes estimators using non-informative and informative priors under different loss functions, we have simulated their statistical properties for different sample sizes and test termination times. In addition, to highlight the practical significance, an illustrative example based on a real-life engineering data is also given. PMID:25993475

Calculation of near optimum design of InP/In(0.53)Ga(0.47)As monolithic tandem solar cells

NASA Technical Reports Server (NTRS)

Renaud, P.; Vilela, M. F.; Freundlich, A.; Medelci, N.; Bensaoula, A.

1994-01-01

An analysis of InP/GaAs tandem solar cell structure has been undertaken to allow for maximum AMO conversion efficiencies (space applications) while still taking into account both the theoretical and technological limitations. The dependence of intrinsic and extrinsic parameters such as diffusion lengths and generation-recombination (GR) lifetimes on N/P and P/N devices performances are clearly demonstrated. We also report for the first time the improvement attainable through the use of a new patterned tunnel junction as the inter cell ohmic interconnect. Such a design minimizes the light absorption in the interconnect region and leads to a noticeable increase in the cell efficiency. Our computations predict 27 percent AMO efficiency for N/P tandems with ideality factor gamma = 2 (GR lifetimes approximately equal 1 micron), and 36 percent for gamma = 1 (GR lifetimes approximately equals 100 microns). The method of optimization and the values of the physical and optical parameters are discussed.

A theoretical analysis of the current-voltage characteristics of solar cells. [and their energy conversion efficiency

NASA Technical Reports Server (NTRS)

Dunbar, P. M.; Hauser, J. R.

1976-01-01

Various mechanisms which limit the conversion efficiency of silicon solar cells were studied. The effects of changes in solar cell geometry such as layer thickness on performance were examined. The effects of various antireflecting layers were also examined. It was found that any single film antireflecting layer results in a significant surface loss of photons. The use of surface texturing techniques or low loss antireflecting layers can enhance by several percentage points the conversion efficiency of silicon cells. The basic differences between n(+)-p-p(+) and p(+)-n-n(+) cells are treated. A significant part of the study was devoted to the importance of surface region lifetime and heavy doping effects on efficiency. Heavy doping bandgap reduction effects are enhanced by low surface layer lifetimes, and conversely, the reduction in solar cell efficiency due to low surface layer lifetime is further enhanced by heavy doping effects. A series of computer studies is reported which seeks to determine the best cell structure and doping levels for maximum efficiency.

Fine structure and lifetime of dark excitons in transition metal dichalcogenide monolayers

NASA Astrophysics Data System (ADS)

Robert, C.; Amand, T.; Cadiz, F.; Lagarde, D.; Courtade, E.; Manca, M.; Taniguchi, T.; Watanabe, K.; Urbaszek, B.; Marie, X.

2017-10-01

The intricate interplay between optically dark and bright excitons governs the light-matter interaction in transition metal dichalcogenide monolayers. We have performed a detailed investigation of the "spin-forbidden" dark excitons in WSe2 monolayers by optical spectroscopy in an out-of-plane magnetic field Bz. In agreement with the theoretical predictions deduced from group theory analysis, magnetophotoluminescence experiments reveal a zero-field splitting δ =0.6 ±0.1 meV between two dark exciton states. The low-energy state is strictly dipole forbidden (perfectly dark) at Bz=0 , while the upper state is partially coupled to light with z polarization ("gray" exciton). The first determination of the dark neutral exciton lifetime τD in a transition metal dichalcogenide monolayer is obtained by time-resolved photoluminescence. We measure τD˜110 ±10 ps for the gray exciton state, i.e., two orders of magnitude longer than the radiative lifetime of the bright neutral exciton at T =12 K .

Cellular Oxygen and Nutrient Sensing in Microgravity Using Time-Resolved Fluorescence Microscopy

NASA Technical Reports Server (NTRS)

Szmacinski, Henryk

2003-01-01

Oxygen and nutrient sensing is fundamental to the understanding of cell growth and metabolism. This requires identification of optical probes and suitable detection technology without complex calibration procedures. Under this project Microcosm developed an experimental technique that allows for simultaneous imaging of intra- and inter-cellular events. The technique consists of frequency-domain Fluorescence Lifetime Imaging Microscopy (FLIM), a set of identified oxygen and pH probes, and methods for fabrication of microsensors. Specifications for electronic and optical components of FLIM instrumentation are provided. Hardware and software were developed for data acquisition and analysis. Principles, procedures, and representative images are demonstrated. Suitable lifetime sensitive oxygen, pH, and glucose probes for intra- and extra-cellular measurements of analyte concentrations have been identified and tested. Lifetime sensing and imaging have been performed using PBS buffer, culture media, and yeast cells as a model systems. Spectral specifications, calibration curves, and probes availability are also provided in the report.

New Labour and Education: An Evidence-Based Analysis

ERIC Educational Resources Information Center

Galton, Maurice

2007-01-01

This article looks at the evidence concerning performance and progress in the primary school over the lifetime of New Labour's tenure in government since 1997. It examines the claims made by New Labour that the Literacy and Numeracy Strategies have been an outstanding success and have changed the ways that teachers teach. On the evidence of the…

Off-line wafer level reliability control: unique measurement method to monitor the lifetime indicator of gate oxide validated within bipolar/CMOS/DMOS technology

NASA Astrophysics Data System (ADS)

Gagnard, Xavier; Bonnaud, Olivier

2000-08-01

We have recently published a paper on a new rapid method for the determination of the lifetime of the gate oxide involved in a Bipolar/CMOS/DMOS technology (BCD). Because this previous method was based on a current measurement with gate voltage as a parameter needing several stress voltages, it was applied only by lot sampling. Thus, we tried to find an indicator in order to monitor the gate oxide lifetime during the wafer level parametric test and involving only one measurement of the device on each wafer test cell. Using the Weibull law and Crook model, combined with our recent model, we have developed a new test method needing only one electrical measurement of MOS capacitor to monitor the quality of the gate oxide. Based also on a current measurement, the parameter is the lifetime indicator of the gate oxide. From the analysis of several wafers, we gave evidence of the possibility to detect a low performance wafer, which corresponds to the infantile failure on the Weibull plot. In order to insert this new method in the BCD parametric program, a parametric flowchart was established. This type of measurement is an important challenges, because the actual measurements, breakdown charge, Qbd, and breakdown electric field, Ebd, at parametric level and Ebd and interface states density, Dit during the process cannot guarantee the gate oxide lifetime all along fabrication process. This indicator measurement is the only one, which predicts the lifetime decrease.

STK/Lifetime as a Replacement for Heritage Orbital Lifetime Software

NASA Technical Reports Server (NTRS)

Dove, Edwin

2004-01-01

The Flight Dynamics Analysis Branch (FDAB) of NASNGSFC is tasked with determining the orbital lifetime of several developmental and operational satellites, which include the Hubble Space Telescope. A DOS based program developed by the FDAB many years ago, called PC Lifetime, is used to determine a satellite s lifetime and could soon be in need of a replacement. STK s Lifetime Object Tool is a possible candidate. Due to the reduced support of the PC Lifetime program, and the growing incompatibility of older programs with new operating systems, a comparative analysis was done to determine if STWLifetime could meet the stringent requirements that were laid before it. The use of highly accurate numerical propagators such as STK s High Precision Orbit Propagator ( OP) and the Goddard Trajectory Determination System (GTDS) provided a basis on which to compare STWLifetime s results. Several test cases were run, but the main four test cases would determine whether or not STWLifetime could be PC- Lifetime s replacement. These four cases include a geotransfer orbit, two circular LEOS, and a Poiar LEO. Following rigorous testmg procedures, a conclusion will be determined. STK has proved to be a versatile program on many satellite missions and the FDAB has high hopes that it can pass FDAB s requirements for orbital lifetime prediction.

The association between smoking prevalence and eating disorders: a systematic review and meta-analysis.

PubMed

Solmi, Marco; Veronese, Nicola; Sergi, Giuseppe; Luchini, Claudio; Favaro, Angela; Santonastaso, Paolo; Vancampfort, Davy; Correll, Christoph U; Ussher, Michael; Thapa-Chhetri, Nita; Fornaro, Michele; Stubbs, Brendon

2016-11-01

Cigarette smoking is associated with severe mental illness, including schizophrenia and bipolar disorder, and with morbidity and mortality, but the association with anorexia (AN), bulimia nervosa (BN) and binge eating disorder (BED) is unclear. This meta-analysis compared the odds of smoking in eating disorders (ED) (ED = AN or BN or BED) versus healthy controls (HC) and calculated the prevalence of smokers in people with ED. Three independent authors searched PubMed, MEDLINE and Scopus from database inception until 31 December 2015 for studies reporting data on life-time or current smoking prevalence in BED, BN and AN with or without control group. Meta-analyses were undertaken, calculating odds ratios (ORs) of life-time smoking in BED, BN, AN versus healthy controls (HCs) or prevalence of smoking in BED, BN and AN with 95% confidence intervals (CI). Thirty-one studies (ED = 8517, controls = 68 335) were meta-analysed. Compared with HCs, there were significantly more smokers among people with BN (life-time OR = 2.165) and BED (life-time OR = 1.792) but not AN (life-time OR = 0.927). BED was associated with smoking the most (life-time prevalence = 47.73%) followed by BN (life-time prevalence = 39.4%) and AN (life-time prevalence = 30.8%). In BN, life-time smoking prevalence was highest in Europe. In AN, higher age moderated both life-time and current smoking prevalence, and body mass index moderated higher life-time smoking prevalence. In BN, female sex moderated higher life-time smoking prevalence. People with binge eating disorder and bulimia nervosa are significantly more likely to be life-time smokers than healthy controls, which is not the case for anorexia nervosa. © 2016 Society for the Study of Addiction.

Experimental analysis of the bearing greases lifetime

NASA Astrophysics Data System (ADS)

Albagachiev, A. U.; Smirnov, N. I.; Prozhega, M. V.; Smirnov, N. N.

2018-04-01

The purpose of the presented work is to increase the lifetime of space mechanisms bearings. The authors reviewed the studies of the bearings and linear mechanisms operating in air and in vacuum. A testing equipment is developed to assess the lubricity and lifetime of greases in the air. Criteria for the evaluation of relative lifetime are defined. Four types of space greases are tested.

The association of lifetime insight and cognition in psychosis.

PubMed

Sánchez-Torres, Ana M; Zarzuela, Amalia; Peralta, Victor; Cuesta, Manuel J

2015-03-01

Poor insight has been related to poor course in psychosis. However, the role of cognition in insight remains unclear. The aim of this study was to examine the influence of cognition and lifetime psychopathological dimensions on insight in psychosis. We followed up 42 patients with psychotic disorders over 10years. Lifetime psychopathological dimensions and cognitive performance were assessed. Patients were divided into two groups by lifetime patterns of insight and compared with 42 healthy volunteers. Lower IQ and poorer social cognition were associated with higher risks of poorer lifetime insight of feeling ill and global insight respectively. Lifetime negative symptoms were associated with a higher risk of poorer lifetime insight into symptoms. Lifetime lack of insight is independent of cognitive impairment in specific domains, except for social cognition. Higher IQ may contribute to better lifetime awareness of illness, while better ability to manage emotions is involved in lifetime global insight. Copyright © 2014 Elsevier B.V. All rights reserved.

DLTPulseGenerator: A library for the simulation of lifetime spectra based on detector-output pulses

NASA Astrophysics Data System (ADS)

Petschke, Danny; Staab, Torsten E. M.

2018-01-01

The quantitative analysis of lifetime spectra relevant in both life and materials sciences presents one of the ill-posed inverse problems and, hence, leads to most stringent requirements on the hardware specifications and the analysis algorithms. Here we present DLTPulseGenerator, a library written in native C++ 11, which provides a simulation of lifetime spectra according to the measurement setup. The simulation is based on pairs of non-TTL detector output-pulses. Those pulses require the Constant Fraction Principle (CFD) for the determination of the exact timing signal and, thus, the calculation of the time difference i.e. the lifetime. To verify the functionality, simulation results were compared to experimentally obtained data using Positron Annihilation Lifetime Spectroscopy (PALS) on pure tin.

Analysis of positron lifetime spectra in polymers

NASA Technical Reports Server (NTRS)

Singh, Jag J.; Mall, Gerald H.; Sprinkle, Danny R.

1988-01-01

A new procedure for analyzing multicomponent positron lifetime spectra in polymers was developed. It requires initial estimates of the lifetimes and the intensities of various components, which are readily obtainable by a standard spectrum stripping process. These initial estimates, after convolution with the timing system resolution function, are then used as the inputs for a nonlinear least squares analysis to compute the estimates that conform to a global error minimization criterion. The convolution integral uses the full experimental resolution function, in contrast to the previous studies where analytical approximations of it were utilized. These concepts were incorporated into a generalized Computer Program for Analyzing Positron Lifetime Spectra (PAPLS) in polymers. Its validity was tested using several artificially generated data sets. These data sets were also analyzed using the widely used POSITRONFIT program. In almost all cases, the PAPLS program gives closer fit to the input values. The new procedure was applied to the analysis of several lifetime spectra measured in metal ion containing Epon-828 samples. The results are described.

Chemometric analysis for extraction of individual fluorescence spectrum and lifetimes from a target mixture

NASA Technical Reports Server (NTRS)

Hallidy, William H. (Inventor); Chin, Robert C. (Inventor)

1999-01-01

The present invention is a system for chemometric analysis for the extraction of the individual component fluorescence spectra and fluorescence lifetimes from a target mixture. The present invention combines a processor with an apparatus for generating an excitation signal to transmit at a target mixture and an apparatus for detecting the emitted signal from the target mixture. The present invention extracts the individual fluorescence spectrum and fluorescence lifetime measurements from the frequency and wavelength data acquired from the emitted signal. The present invention uses an iterative solution that first requires the initialization of several decision variables and the initial approximation determinations of intermediate matrices. The iterative solution compares the decision variables for convergence to see if further approximation determinations are necessary. If the solution converges, the present invention then determines the reduced best fit error for the analysis of the individual fluorescence lifetime and the fluorescence spectrum before extracting the individual fluorescence lifetime and fluorescence spectrum from the emitted signal of the target mixture.

Coupled modeling of a directly heated tubular solar receiver for supercritical carbon dioxide Brayton cycle: Structural and creep-fatigue evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortega, Jesus; Khivsara, Sagar; Christian, Joshua

A supercritical carbon dioxide (sCO 2) Brayton cycle is an emerging high energy-density cycle undergoing extensive research due to the appealing thermo-physical properties of sCO 2 and single phase operation. Development of a solar receiver capable of delivering sCO 2 at 20 MPa and 700 °C is required for implementation of the high efficiency (~50%) solar powered sCO 2 Brayton cycle. In this work, extensive candidate materials are review along with tube size optimization using the ASME Boiler and Pressure Vessel Code. Moreover, temperature and pressure distribution obtained from the thermal-fluid modeling (presented in a complementary publication) are used tomore » evaluate the thermal and mechanical stresses along with detailed creep-fatigue analysis of the tubes. The lifetime performance of the receiver tubes were approximated using the resulting body stresses. A cyclic loading analysis is performed by coupling the Strain-Life approach and the Larson-Miller creep model. The structural integrity of the receiver was examined and it was found that the stresses can be withstood by specific tubes, determined by a parametric geometric analysis. Furthermore, the creep-fatigue analysis displayed the damage accumulation due to cycling and the permanent deformation on the tubes showed that the tubes can operate for the full lifetime of the receiver.« less

Coupled modeling of a directly heated tubular solar receiver for supercritical carbon dioxide Brayton cycle: Structural and creep-fatigue evaluation

DOE PAGES

Ortega, Jesus; Khivsara, Sagar; Christian, Joshua; ...

2016-06-06

A supercritical carbon dioxide (sCO 2) Brayton cycle is an emerging high energy-density cycle undergoing extensive research due to the appealing thermo-physical properties of sCO 2 and single phase operation. Development of a solar receiver capable of delivering sCO 2 at 20 MPa and 700 °C is required for implementation of the high efficiency (~50%) solar powered sCO 2 Brayton cycle. In this work, extensive candidate materials are review along with tube size optimization using the ASME Boiler and Pressure Vessel Code. Moreover, temperature and pressure distribution obtained from the thermal-fluid modeling (presented in a complementary publication) are used tomore » evaluate the thermal and mechanical stresses along with detailed creep-fatigue analysis of the tubes. The lifetime performance of the receiver tubes were approximated using the resulting body stresses. A cyclic loading analysis is performed by coupling the Strain-Life approach and the Larson-Miller creep model. The structural integrity of the receiver was examined and it was found that the stresses can be withstood by specific tubes, determined by a parametric geometric analysis. Furthermore, the creep-fatigue analysis displayed the damage accumulation due to cycling and the permanent deformation on the tubes showed that the tubes can operate for the full lifetime of the receiver.« less

Higher speed VCSELs by photon lifetime reduction

NASA Astrophysics Data System (ADS)

Westbergh, Petter; Gustavsson, Johan S.; Kögel, Benjamin; Haglund, Åsa; Larsson, Anders; Joel, Andrew

2011-03-01

The impedance characteristics and the effects of photon lifetime reduction on the performance of high-speed 850 nm VCSELs are investigated. Through S11 measurements and equivalent circuit modeling we show that the parasitic mesa capacitance can be significantly reduced by using multiple oxide layers. By performing a shallow surface etch (25 - 55 nm) on the fabricated VCSELs, we are able to reduce the photon lifetime by up to 80% and thereby significantly improve both static and dynamic properties of the VCSELs. By optimizing the photon lifetime we are able to enhance the 3dB modulation bandwidth of 7 μm oxide aperture VCSELs from 15 GHz to 23 GHz and finally demonstrate errorfree transmission at up to 40 Gbit/s.

Evaluating the Life Cycle Environmental Benefits and Trade-Offs of Water Reuse Systems for Net-Zero Buildings.

PubMed

Hasik, Vaclav; Anderson, Naomi E; Collinge, William O; Thiel, Cassandra L; Khanna, Vikas; Wirick, Jason; Piacentini, Richard; Landis, Amy E; Bilec, Melissa M

2017-02-07

Aging water infrastructure and increased water scarcity have resulted in higher interest in water reuse and decentralization. Rating systems for high-performance buildings implicitly promote the use of building-scale, decentralized water supply and treatment technologies. It is important to recognize the potential benefits and trade-offs of decentralized and centralized water systems in the context of high-performance buildings. For this reason and to fill a gap in the current literature, we completed a life cycle assessment (LCA) of the decentralized water system of a high-performance, net-zero energy, net-zero water building (NZB) that received multiple green building certifications and compared the results with two modeled buildings (conventional and water efficient) using centralized water systems. We investigated the NZB's impacts over varying lifetimes, conducted a break-even analysis, and included Monte Carlo uncertainty analysis. The results show that, although the NZB performs better in most categories than the conventional building, the water efficient building generally outperforms the NZB. The lifetime of the NZB, septic tank aeration, and use of solar energy have been found to be important factors in the NZB's impacts. While these findings are specific to the case study building, location, and treatment technologies, the framework for comparison of water and wastewater impacts of various buildings can be applied during building design to aid decision making. As we design and operate high-performance buildings, the potential trade-offs of advanced decentralized water treatment systems should be considered.

Characterization of ErAs:GaAs and LuAs:GaAs Superlattice Structures for Continuous-Wave Terahertz Wave Generation through Plasmonic Photomixing

NASA Astrophysics Data System (ADS)

Yang, Shang-Hua; Salas, Rodolfo; Krivoy, Erica M.; Nair, Hari P.; Bank, Seth R.; Jarrahi, Mona

2016-07-01

We investigate the impact of ErAs:GaAs and LuAs:GaAs superlattice structures with different LuAs/ErAs nanoparticle depositions and superlattice geometries on terahertz radiation properties of plasmonic photomixers operating at a 780-nm optical wavelength. Our analysis indicates the crucial impact of carrier drift velocity and carrier lifetime on the performance of plasmonic photomixers. While higher carrier drift velocities enable higher optical-to-terahertz conversion efficiencies by offering higher quantum efficiencies, shorter carrier lifetimes allow achieving higher optical-to-terahertz conversion efficiencies by mitigating the negative impact of destructive terahertz radiation from slow photocarriers and preventing the carrier screening effect.

An Evaluation of Liquid, Solid, and Grease Lubricants for Space Mechanisms Using a Spiral Orbit Tribometer

NASA Technical Reports Server (NTRS)

Buttery, Michael

2010-01-01

We present the findings of the test program performed by The European Space Tribology Laboratory (ESTL) to evaluate the performance (friction and lifetime) of a number of space lubricants under vacuum using a Spiral Orbit Tribometer (SOT). Focus was given to a comparison of various popular space oils, a comparison study between the old and new MAPLUB grease formulations, and the performance of commonly used solid lubricants under various conditions. Tests demonstrated that the lifetimes of hydrocarbon NYE oils 2001 & 2001A outperformed those of the perfluroropolyalkylether (PFPE) oils Fomblin Z25 & Z60, though these pairs displayed similar behavior. This relationship was also generally seen for greases; with the lifetimes of the multiple alkylated cyclopentane (MAC)-based greases being extended in comparison to the PFPE-based greases. Testing on greases also demonstrated similar performance between the old (-a) and new (-b) formulations when considering PFPE-based MAPLUB greases, and indeed for all tested PFPE-based non-MAPLUB greases, but significantly shorter lifetimes for the new formulations when considering MAC-based MAPLUB greases. MAPLUB MAC greases containing molybdenum disulphide (MoS2) thickener were also found to display reduced lifetimes. For solid lubricants, lead displayed significantly extended lifetimes over MoS2, speculated to be caused by redistribution of lead from the ball onto all contact surfaces during the test. Friction coefficients were seen to be some 2.5x higher for lead than for MoS2 under similar conditions, a result that corresponds well with conventional bearing tests. The work described was performed under contract for the European Space Agency as part of the Tribology Applications Program, with all funding for testing and apparatus provided by European Space Agency (ESA).

Methodological considerations for global analysis of cellular FLIM/FRET measurements

NASA Astrophysics Data System (ADS)

Adbul Rahim, Nur Aida; Pelet, Serge; Kamm, Roger D.; So, Peter T. C.

2012-02-01

Global algorithms can improve the analysis of fluorescence energy transfer (FRET) measurement based on fluorescence lifetime microscopy. However, global analysis of FRET data is also susceptible to experimental artifacts. This work examines several common artifacts and suggests remedial experimental protocols. Specifically, we examined the accuracy of different methods for instrument response extraction and propose an adaptive method based on the mean lifetime of fluorescent proteins. We further examined the effects of image segmentation and a priori constraints on the accuracy of lifetime extraction. Methods to test the applicability of global analysis on cellular data are proposed and demonstrated. The accuracy of global fitting degrades with lower photon count. By systematically tracking the effect of the minimum photon count on lifetime and FRET prefactors when carrying out global analysis, we demonstrate a correction procedure to recover the correct FRET parameters, allowing us to obtain protein interaction information even in dim cellular regions with photon counts as low as 100 per decay curve.

Development of high performance refractory fibers with enhanced insulating properties and longer service lifetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, P.C.; DePoorter, G.L.; Munoz, D.R.

1991-02-01

We have initiated a three phase investigation of the development of high performance refractory fibers with enhanced insulating properties and longer usable lifetimes. This report presents the results of the first phase of the study, performed from Aug. 1989 through Feb. 1991, which shows that significant energy saving are possible through the use of high temperature insulating fibers that better retain their efficient insulating properties during the service lifetime of the fibers. The remaining phases of this program include the pilot scale development and then full scale production feasibility development and evaluation of enhanced high temperature refractory insulting fibers. Thismore » first proof of principle phase of the program presents a summary of the current use patterns of refractory fibers, a laboratory evaluation of the high temperature performance characteristics of selected typical refractory fibers and an analysis of the potential energy savings through the use of enhanced refractory fibers. The current use patterns of refractory fibers span a wide range of industries and high temperature furnaces within those industries. The majority of high temperature fiber applications are in furnaces operating between 2000 and 26000{degrees}F. The fibers used in furnaces operating within this range provide attractive thermal resistance and low thermal storage at reasonable cost. A series of heat treatment studies performed for this phase of the program has shown that the refractory fibers, as initially manufactured, have attractive thermal conductivities for high temperature applications but the fibers go through rapid devitrification and subsequent crystal growth upon high temperature exposure. Development of improved fibers, maintaining the favorable characteristics of the existing as-manufactured fibers, could save between 1 and 4% of the energy consumed in high temperature furnaces using refractory fibers.« less

Label-free separation of human embryonic stem cells and their differentiating progenies by phasor fluorescence lifetime microscopy

NASA Astrophysics Data System (ADS)

Stringari, Chiara; Sierra, Robert; Donovan, Peter J.; Gratton, Enrico

2012-04-01

We develop a label-free optical technique to image and discriminate undifferentiated human embryonic stem cells (hESCs) from their differentiating progenies in vitro. Using intrinsic cellular fluorophores, we perform fluorescence lifetime microscopy (FLIM) and phasor analysis to obtain hESC metabolic signatures. We identify two optical biomarkers to define the differentiation status of hESCs: Nicotinamide adenine dinucleotide (NADH) and lipid droplet-associated granules (LDAGs). These granules have a unique lifetime signature and could be formed by the interaction of reactive oxygen species and unsaturated metabolic precursor that are known to be abundant in hESC. Changes in the relative concentrations of these two intrinsic biomarkers allow for the discrimination of undifferentiated hESCs from differentiating hESCs. During early hESC differentiation we show that NADH concentrations increase, while the concentration of LDAGs decrease. These results are in agreement with a decrease in oxidative phosphorylation rate. Single-cell phasor FLIM signatures reveal an increased heterogeneity in the metabolic states of differentiating H9 and H1 hESC colonies. This technique is a promising noninvasive tool to monitor hESC metabolism during differentiation, which can have applications in high throughput analysis, drug screening, functional metabolomics and induced pluripotent stem cell generation.

Cost-effectiveness of an HPV self-collection campaign in Uganda: comparing models for delivery of cervical cancer screening in a low-income setting

PubMed Central

Campos, Nicole G; Tsu, Vivien; Jeronimo, Jose; Njama-Meya, Denise; Mvundura, Mercy; Kim, Jane J

2017-01-01

Abstract With the availability of a low-cost HPV DNA test that can be administered by either a healthcare provider or a woman herself, programme planners require information on the costs and cost-effectiveness of implementing cervical cancer screening programmes in low-resource settings under different models of healthcare delivery. Using data from the START-UP demonstration project and a micro-costing approach, we estimated the health and economic impact of once-in-a-lifetime HPV self-collection campaign relative to clinic-based provider-collection of HPV specimens in Uganda. We used an individual-based Monte Carlo simulation model of the natural history of HPV and cervical cancer to estimate lifetime health and economic outcomes associated with screening with HPV DNA testing once in a lifetime (clinic-based provider-collection vs a self-collection campaign). Test performance and cost data were obtained from the START-UP demonstration project using a micro-costing approach. Model outcomes included lifetime risk of cervical cancer, total lifetime costs (in 2011 international dollars [I$]), and life expectancy. Cost-effectiveness ratios were expressed using incremental cost-effectiveness ratios (ICERs). When both strategies achieved 75% population coverage, ICERs were below Uganda’s per capita GDP (self-collection: I$80 per year of life saved [YLS]; provider-collection: I$120 per YLS). When the self-collection campaign achieved coverage gains of 15–20%, it was more effective than provider-collection, and had a lower ICER unless coverage with both strategies was 50% or less. Findings were sensitive to cryotherapy compliance among screen-positive women and relative HPV test performance. The primary limitation of this analysis is that self-collection costs are based on a hypothetical campaign but are based on unit costs from Uganda. Once-in-a-lifetime screening with HPV self-collection may be very cost-effective and reduce cervical cancer risk by > 20% if coverage is high. Demonstration projects will be needed to confirm the validity of our logistical, costing and compliance assumptions. PMID:28369405

Cost-effectiveness of an HPV self-collection campaign in Uganda: comparing models for delivery of cervical cancer screening in a low-income setting.

PubMed

Campos, Nicole G; Tsu, Vivien; Jeronimo, Jose; Njama-Meya, Denise; Mvundura, Mercy; Kim, Jane J

2017-09-01

With the availability of a low-cost HPV DNA test that can be administered by either a healthcare provider or a woman herself, programme planners require information on the costs and cost-effectiveness of implementing cervical cancer screening programmes in low-resource settings under different models of healthcare delivery. Using data from the START-UP demonstration project and a micro-costing approach, we estimated the health and economic impact of once-in-a-lifetime HPV self-collection campaign relative to clinic-based provider-collection of HPV specimens in Uganda. We used an individual-based Monte Carlo simulation model of the natural history of HPV and cervical cancer to estimate lifetime health and economic outcomes associated with screening with HPV DNA testing once in a lifetime (clinic-based provider-collection vs a self-collection campaign). Test performance and cost data were obtained from the START-UP demonstration project using a micro-costing approach. Model outcomes included lifetime risk of cervical cancer, total lifetime costs (in 2011 international dollars [I$]), and life expectancy. Cost-effectiveness ratios were expressed using incremental cost-effectiveness ratios (ICERs). When both strategies achieved 75% population coverage, ICERs were below Uganda's per capita GDP (self-collection: I$80 per year of life saved [YLS]; provider-collection: I$120 per YLS). When the self-collection campaign achieved coverage gains of 15-20%, it was more effective than provider-collection, and had a lower ICER unless coverage with both strategies was 50% or less. Findings were sensitive to cryotherapy compliance among screen-positive women and relative HPV test performance. The primary limitation of this analysis is that self-collection costs are based on a hypothetical campaign but are based on unit costs from Uganda. Once-in-a-lifetime screening with HPV self-collection may be very cost-effective and reduce cervical cancer risk by > 20% if coverage is high. Demonstration projects will be needed to confirm the validity of our logistical, costing and compliance assumptions. © The Author 2017. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine.

Battery Lifetime Analysis and Simulation Tool (BLAST) Documentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neubauer, J.

2014-12-01

The deployment and use of lithium-ion (Li-ion) batteries in automotive and stationary energy storage applications must be optimized to justify their high up-front costs. Given that batteries degrade with use and storage, such optimizations must evaluate many years of operation. As the degradation mechanisms are sensitive to temperature, state-of-charge (SOC) histories, current levels, and cycle depth and frequency, it is important to model both the battery and the application to a high level of detail to ensure battery response is accurately predicted. To address these issues, the National Renewable Energy Laboratory (NREL) has developed the Battery Lifetime Analysis and Simulationmore » Tool (BLAST) suite. This suite of tools pairs NREL’s high-fidelity battery degradation model with a battery electrical and thermal performance model, application-specific electrical and thermal performance models of the larger system (e.g., an electric vehicle), application-specific system use data (e.g., vehicle travel patterns and driving data), and historic climate data from cities across the United States. This provides highly realistic long-term predictions of battery response and thereby enables quantitative comparisons of varied battery use strategies.« less

Throttling Impacts on Hall Thruster Performance, Erosion, and Qualification for NASA Science Missions

NASA Technical Reports Server (NTRS)

Dankanich, John W.; DeHoyos, Amado

2007-01-01

With the SMART-1, Department of Defense, and commercial industry successes in Hall thruster technologies, NASA has started considering Hall thrusters for science missions. The recent Discovery proposals included a Hall thruster science mission and the In-Space Propulsion Project is investing in Hall thruster technologies. As the confidence in Hall thrusters improve, ambitious multi-thruster missions are being considered. Science missions often require large throttling ranges due to the 1/r(sup 2) power drop-off from the sun. Deep throttling of Hall thrusters will impact the overall system performance. Also, Hall thrusters can be throttled with both current and voltage, impacting erosion rates and performance. Last, electric propulsion thruster lifetime qualification has previously been conducted with long duration full power tests. Full power tests may not be appropriate for NASA science missions, and a combination of lifetime testing at various power levels with sufficient analysis is recommended. Analyses of various science missions and throttling schemes using the Aerojet BPT-4000 and NASA 103M HiVHAC thruster are presented.

Influence of chemical bonds on the lifetime of the molecular-field-split 2p levels in H{sub 2}S

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bueno, Andre Machado; Brito, Arnaldo Naves de; Fink, Reinhold F.

Different lifetime broadenings in molecular-field-split 2p core levels in H{sub 2}S are predicted theoretically and are identified in an experimental investigation of the S 2p Auger electron spectrum. The measurements were performed for the transition to the vibrationally resolved X{sup 1}A{sub 1} ground state of H{sub 2}S{sup 2+}. The lifetimes of the 3e{sub 1/2} and 5e{sub 1/2} levels of the 2p ionized molecule are found to be 64 and 74 meV, respectively. This unambiguous determination of the lifetime difference of 10{+-}1 meV is only possible as the 4e{sub 1/2}{yields}X{sup 1}A{sub 1}(2b{sub 1}{sup -2}) decay channel that overlaps the 5e{sub 1/2}{yields}X{supmore » 1}A{sub 1}(2b{sub 1}{sup -2}) channel is practically suppressed in Auger decay in H{sub 2}S. The lifetime difference is confirmed by ab initio calculations. A theoretical analysis shows that it results from the mutual orientation of the core hole in the intermediate states and the valence electron density in the sulfur 3p orbitals. Both are strongly influenced by the chemical bond. Thus the observed effect is the direct result of a fundamental property of molecular electronic structure.« less

A Hybrid Lifetime Extended Directional Approach for WBANs

PubMed Central

Li, Changle; Yuan, Xiaoming; Yang, Li; Song, Yueyang

2015-01-01

Wireless Body Area Networks (WBANs) can provide real-time and reliable health monitoring, attributing to the human-centered and sensor interoperability properties. WBANs have become a key component of the ubiquitous eHealth (electronic health) revolution that prospers on the basis of information and communication technologies. The prime consideration in WBAN is how to maximize the network lifetime with battery-powered sensor nodes in energy constraint. Novel solutions in Medium Access Control (MAC) protocols are imperative to satisfy the particular BAN scenario and the need of excellent energy efficiency in healthcare applications. In this paper, we propose a hybrid Lifetime Extended Directional Approach (LEDA) MAC protocol based on IEEE 802.15.6 to reduce energy consumption and prolong network lifetime. The LEDA MAC protocol takes full advantages of directional superiority in energy saving that employs multi-beam directional mode in Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) and single-beam directional mode in Time Division Multiple Access (TDMA) for alternative in data reservation and transmission according to the traffic varieties. Moreover, the impacts of some inherent problems of directional antennas such as deafness and hidden terminal problem can be decreased owing to that all nodes generate individual beam according to user priorities designated. Furthermore, LEDA MAC employs a Dynamic Polled Allocation Period (DPAP) for burst data transmissions to increase the network reliability and adaptability. Extensive analysis and simulation results show that the proposed LEDA MAC protocol achieves extended network lifetime with improved performance compared with IEEE 802.15.6. PMID:26556357

A Lifetime Maximization Relay Selection Scheme in Wireless Body Area Networks.

PubMed

Zhang, Yu; Zhang, Bing; Zhang, Shi

2017-06-02

Network Lifetime is one of the most important metrics in Wireless Body Area Networks (WBANs). In this paper, a relay selection scheme is proposed under the topology constrains specified in the IEEE 802.15.6 standard to maximize the lifetime of WBANs through formulating and solving an optimization problem where relay selection of each node acts as optimization variable. Considering the diversity of the sensor nodes in WBANs, the optimization problem takes not only energy consumption rate but also energy difference among sensor nodes into account to improve the network lifetime performance. Since it is Non-deterministic Polynomial-hard (NP-hard) and intractable, a heuristic solution is then designed to rapidly address the optimization. The simulation results indicate that the proposed relay selection scheme has better performance in network lifetime compared with existing algorithms and that the heuristic solution has low time complexity with only a negligible performance degradation gap from optimal value. Furthermore, we also conduct simulations based on a general WBAN model to comprehensively illustrate the advantages of the proposed algorithm. At the end of the evaluation, we validate the feasibility of our proposed scheme via an implementation discussion.

Glass Fibre/Epoxy Resin Interface Life-Time Prediction.

DTIC Science & Technology

1983-04-01

RD-Ai32 26 GLASS FIBRE /POXY RESIN INTERFACE LIFE-TIME PREDICTION 1/1 (U) BRISTOL UNIV (ENGLAND) H H WILLS PHYSICS LAB K H RSHBEE ET AL. APR 83...D 3005-MS GLASS FIBRE /EPOXY RESIN INTERFACE LIFE-TIME PREDICTION - Final Report by K H G Ashbee, Principal Investigator R Ho~l J P Sargent Elizabeth...REPORT h PERIOD COVERED. Glass Fibre /Epoxy Resin Interface Life-time F-inal Technical 11’ port PreictonApril 1981 - A:’ril 1983 6. PERFORMING ORG. REPORT

Nondestructive assessment of collagen hydrogel cross-linking using time-resolved autofluorescence imaging.

PubMed

Sherlock, Benjamin E; Harvestine, Jenna N; Mitra, Debika; Haudenschild, Anne; Hu, Jerry; Athanasiou, Kyriacos A; Leach, J Kent; Marcu, Laura

2018-03-01

We investigate the use of a fiber-based, multispectral fluorescence lifetime imaging (FLIm) system to nondestructively monitor changes in mechanical properties of collagen hydrogels caused by controlled application of widely used cross-linking agents, glutaraldehyde (GTA) and ribose. Postcross-linking, fluorescence lifetime images are acquired prior to the hydrogels being processed by rheological or tensile testing to directly probe gel mechanical properties. To preserve the sterility of the ribose-treated gels, FLIm is performed inside a biosafety cabinet (BSC). A pairwise correlation analysis is used to quantify the relationship between mean hydrogel fluorescence lifetimes and the storage or Young's moduli of the gels. In the GTA study, we observe strong and specific correlations between fluorescence lifetime and the storage and Young's moduli. Similar correlations are not observed in the ribose study and we postulate a reason for this. Finally, we demonstrate the ability of FLIm to longitudinally monitor dynamic cross-link formation. The strength of the GTA correlations and deployment of our fiber-based FLIm system inside the aseptic environment of a BSC suggests that this technique may be a valuable tool for the tissue engineering community where longitudinal assessment of tissue construct maturation in vitro is highly desirable. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Fluorescence lifetime imaging of skin cancer

NASA Astrophysics Data System (ADS)

Patalay, Rakesh; Talbot, Clifford; Munro, Ian; Breunig, Hans Georg; König, Karsten; Alexandrov, Yuri; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Chris

2011-03-01

Fluorescence intensity imaging and fluorescence lifetime imaging microscopy (FLIM) using two photon microscopy (TPM) have been used to study tissue autofluorescence in ex vivo skin cancer samples. A commercially available system (DermaInspect®) was modified to collect fluorescence intensity and lifetimes in two spectral channels using time correlated single photon counting and depth-resolved steady state measurements of the fluorescence emission spectrum. Uniquely, image segmentation has been used to allow fluorescence lifetimes to be calculated for each cell. An analysis of lifetime values obtained from a range of pigmented and non-pigmented lesions will be presented.

AMOLED (active matrix OLED) functionality and usable lifetime at temperature

NASA Astrophysics Data System (ADS)

Fellowes, David A.; Wood, Michael V.; Prache, Olivier; Jones, Susan

2005-05-01

Active Matrix Organic Light Emitting Diode (AMOLED) displays are known to exhibit high levels of performance, and these levels of performance have continually been improved over time with new materials and electronics design. eMagin Corporation developed a manually adjustable temperature compensation circuit with brightness control to allow for excellent performance over a wide temperature range. Night Vision and Electronic Sensors Directorate (US Army) tested the performance and survivability of a number of AMOLED displays in a temperature chamber over a range from -55°C to +85°C. Although device performance of AMOLEDs has always been its strong suit, the issue of usable display lifetimes for military applications continues to be an area of discussion and research. eMagin has made improvements in OLED materials and worked towards the development of a better understanding of usable lifetime for operation in a military system. NVESD ran luminance degradation tests of AMOLED panels at 50°C and at ambient to characterize the lifetime of AMOLED devices. The result is a better understanding of the applicability of AMOLEDs in military systems: where good fits are made, and where further development is needed.

Determination of several families of phytochemicals in different pre-cooked convenience vegetables: effect of lifetime and cooking.

PubMed

Alarcón-Flores, M Isabel; Hernández-Sánchez, Francisco; Romero-González, Roberto; Plaza-Bolaños, Patricia; Martínez Vidal, J Luis; Garrido Frenich, Antonia

2014-11-01

Phytochemicals content, including several families such as phenolic acids, isoflavones, flavones, flavonols, isothiocyanates, and glucosinolates, was determined in pre-cooked convenience vegetables by ultra high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS). It was observed that there is not a common behavior of the individual concentration of phytochemicals during the lifetime and cooking of the matrix, and compounds change their concentration without a specific trend. It was observed that neither lifetime nor cooking process have significant effects on the total content of phytochemicals except in broccoli, although some changes in the individual content of the target compounds were observed, suggesting that interconversion processes could be performed during the lifetime and/or cooking process of the product.

User's manual for the Simulated Life Analysis of Vehicle Elements (SLAVE) model

NASA Technical Reports Server (NTRS)

Paul, D. D., Jr.

1972-01-01

The simulated life analysis of vehicle elements model was designed to perform statistical simulation studies for any constant loss rate. The outputs of the model consist of the total number of stages required, stages successfully completing their lifetime, and average stage flight life. This report contains a complete description of the model. Users' instructions and interpretation of input and output data are presented such that a user with little or no prior programming knowledge can successfully implement the program.

Results and Systematic Studies of the UCN Lifetime Experiment at NIST

NASA Astrophysics Data System (ADS)

Huffer, Craig Reeves

The neutron beta-decay lifetime is important in understanding weak interactions in the framework of the Standard Model, and it is an input to nuclear astrophysics and Big Bang Nucleosynthesis. Current measurements of the neutron beta-decay lifetime disagree, which has motivated additional experiments that are sensitive to different sets of systematic effects. An effort continues at the NIST Center for Neutron Research (NCNR) to improve the statistical and systematic limitations of an experiment to measure the neutron beta-decay lifetime using magnetically trapped UCN. In the experiment, a monoenergetic 0:89 nm cold neutron is incident on a superfluid 4He target within the minimum field region of an Ioffe type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (≈ 200 neV), and those in the appropriate spin state become trapped. The inverse process, upscattering of UCN, is suppressed by the low phonon density in the < 300 mK helium. When the neutron decays, the energetic electron creates EUV scintillation light, which is down-converted and transported out of the cell to PMTs operated at room temperature. With this method, the decay of the UCN population can be monitored in situ. The apparatus, analysis, data, and systematics will be discussed. After accounting for the systematic effects the measured lifetime disagrees with the current PDG mean neutron beta-decay lifetime by about 9 of our standard deviations, which is a strong indication of unaccounted for systematic effects. Additional 3He contamination will be shown to be the most likely candidate for the additional systematic shift, which motivated the commissioning and initial operation of a heat flush purifier for purifying additional 4He. This work ends with a description of the 4He purifier and its performance.

Degradation modeling of high temperature proton exchange membrane fuel cells using dual time scale simulation

NASA Astrophysics Data System (ADS)

Pohl, E.; Maximini, M.; Bauschulte, A.; vom Schloß, J.; Hermanns, R. T. E.

2015-02-01

HT-PEM fuel cells suffer from performance losses due to degradation effects. Therefore, the durability of HT-PEM is currently an important factor of research and development. In this paper a novel approach is presented for an integrated short term and long term simulation of HT-PEM accelerated lifetime testing. The physical phenomena of short term and long term effects are commonly modeled separately due to the different time scales. However, in accelerated lifetime testing, long term degradation effects have a crucial impact on the short term dynamics. Our approach addresses this problem by applying a novel method for dual time scale simulation. A transient system simulation is performed for an open voltage cycle test on a HT-PEM fuel cell for a physical time of 35 days. The analysis describes the system dynamics by numerical electrochemical impedance spectroscopy. Furthermore, a performance assessment is performed in order to demonstrate the efficiency of the approach. The presented approach reduces the simulation time by approximately 73% compared to conventional simulation approach without losing too much accuracy. The approach promises a comprehensive perspective considering short term dynamic behavior and long term degradation effects.

MATERIALS DEGRADATION ANALYSIS AND DEVELOPMENT TO ENABLE ULTRA LOW COST, WEB-PROCESSED WHITE P-OLED FOR SSL

DOE Office of Scientific and Technical Information (OSTI.GOV)

DR. DEVIN MACKENZIE

2011-12-13

Progress over Phase II of DE-FG02-07ER86293 'Materials Degradation Analysis and Development to Enable Ultra Low Cost, Web-Processed White P-OLED for SSL' was initially rapid in terms of device performance improvements. We exceeded our device luminance lifetime goals for printed flexible white OLEDs as laid out in our project proposal. Our Phase II performance target was to demonstrate >1500 hours luminance lifetime at 100 Cd/m2 from a printed flexible device. We now have R&D devices well in excess of 8000 hrs lifetime at 100 Cd/m2, tested in air. We also were able to produce devices which met the voltage target ofmore » >1500 hours below 15V operation. After completing the initial performance milestones, we went on to focus on color-related degradation issues which were cited as important to commercialization of the technology by our manufacturing partners. We also put additional focus on cathode work as the active material development that occurred over the STTR time period required an adaptation of the cathode from the original cathode formulations which were developed based on previous generation active layer materials. We were able to improve compatibility of the cathode with some of the newer generation active layer materials and improve device yield and voltage behavior. An additional objective of the initial Phase II was to further develop the underlying manufacturing technology and real-life product specifications. This is a key requirement that must be met to ensure eventual commercialization of this DOE-funded technology. The link between commercial investment for full commercialization and R&D efforts in OLED solid State Lighting is often a large one. Add-Vision's lower cost, printed OLED manufacturing approach is an attraction, but close engagement with manufacturing partners and addressing customer specifications is a very important link. Manufacturing technology encompasses development of moisture reduction encapsulation technology, improved cost performance, and reductions in operating voltage through thinner and higher uniformity active device layers. We have now installed a pilot encapsulation system at AVI for controlled, high throughput lamination encapsulation of flexible OLEDs in a novel process. Along with this, we have developed, with our materials supply partners, adhesives, barrier films and other encapsulation materials and we are showing total air product lifetimes in the 2-4 years range from a process consistent with our throughput goals of {approx}1M device per month ({approx}30,000 sq. ft. of processed OLEDs). Within the last year of the project, we have been working to introduce the manufacturing improvements made in our LEP deposition and annealing process to our commercial partners. Based on the success of this, a pilot scale-up program was begun. During this process, Add-Vision was acquired by a strategic partner, in no small part, because of the promise of future success of the technology as evidenced by our commercial partners pilot scale-up plans. Overall, the performance, manufacturing and product work in this project has been successful. Additional analysis and device work at LBL has also shown a unique adhesion change with device bias stressing which may result from active layer polymer cross-linking during bias stressing of device. It was shown that even small bias stresses, as a fraction of a full device lifetime stress period, result in measurable chemical change in the device. Further work needs to be conducted to fully understand the chemical nature of this interaction. Elucidation of this effect would enable doped OLED formulation to be engineered to suppress this effect and further extend lifetimes and reduce voltage climb.« less

The roles of carrier concentration and interface, bulk, and grain-boundary recombination for 25% efficient CdTe solar cells

DOE PAGES

Kanevce, A.; Reese, Matthew O.; Barnes, T. M.; ...

2017-06-06

CdTe devices have reached efficiencies of 22% due to continuing improvements in bulk material properties, including minority carrier lifetime. Device modeling has helped to guide these device improvements by quantifying the impacts of material properties and different device designs on device performance. One of the barriers to truly predictive device modeling is the interdependence of these material properties. For example, interfaces become more critical as bulk properties, particularly, hole density and carrier lifetime, increase. We present device-modeling analyses that describe the effects of recombination at the interfaces and grain boundaries as lifetime and doping of the CdTe layer change. Themore » doping and lifetime should be priorities for maximizing open-circuit voltage (V oc) and efficiency improvements. However, interface and grain boundary recombination become bottlenecks for device performance at increased lifetime and doping levels. In conclusion, this work quantifies and discusses these emerging challenges for next-generation CdTe device efficiency.« less

Vapour-Deposited Cesium Lead Iodide Perovskites: Microsecond Charge Carrier Lifetimes and Enhanced Photovoltaic Performance

PubMed Central

2017-01-01

Metal halide perovskites such as methylammonium lead iodide (MAPbI3) are highly promising materials for photovoltaics. However, the relationship between the organic nature of the cation and the optoelectronic quality remains debated. In this work, we investigate the optoelectronic properties of fully inorganic vapour-deposited and spin-coated black-phase CsPbI3 thin films. Using the time-resolved microwave conductivity technique, we measure charge carrier mobilities up to 25 cm2/(V s) and impressively long charge carrier lifetimes exceeding 10 μs for vapour-deposited CsPbI3, while the carrier lifetime reaches less than 0.2 μs in the spin-coated samples. Finally, we show that these improved lifetimes result in enhanced device performance with power conversion efficiencies close to 9%. Altogether, these results suggest that the charge carrier mobility and recombination lifetime are mainly dictated by the inorganic framework rather than the organic nature of the cation. PMID:28852710

Lifetime Estimation of a Time Projection Chamber X-ray Polarimeter

NASA Technical Reports Server (NTRS)

Hill, Joanne E.; Black, J. Kevin; Brieda, Lubos; Dickens, Patsy L.; deGarcia, Kristina Montt; Hawk, Douglas L.; Hayato, Asami; Jahoda, Keith; Mohammed, Jelila

2013-01-01

The Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray polarimeter Instrument (XPI) was designed to measure the polarization of 23 sources over the course of its 9 month mission. The XPI design consists of two telescopes each with a polarimeter assembly at the focus of a grazing incidence mirror. To make sensitive polarization measurements the GEMS Polarimeter Assembly (PA) employed a gas detection system based on a Time Projection Chamber (TPC) technique. Gas detectors are inherently at risk of degraded performance arising from contamination from outgassing of internal detector components or due to loss of gas. This paper describes the design and the materials used to build a prototype of the flight polarimeter with the required GEMS lifetime. We report the results from outgassing measurements of the polarimeter subassemblies and assemblies, enclosure seal tests, life tests, and performance tests that demonstrate that the GEMS lifetime is achievable. Finally we report performance measurements and the lifetime enhancement from the use of a getter.

Effect of pharmacologically induced retinal degeneration on retinal autofluorescence lifetimes in mice.

PubMed

Dysli, Chantal; Dysli, Muriel; Zinkernagel, Martin S; Enzmann, Volker

2016-12-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) was used to investigate retinal autofluorescence lifetimes in mouse models of pharmacologically induced retinal degeneration over time. Sodium iodate (NaIO 3 , 35 mg/kg intravenously) was used to induce retinal pigment epithelium (RPE) degeneration with subsequent loss of photoreceptors (PR) whereas N-methyl-N-nitrosourea (MNU, 45 mg/kg intraperitoneally) was employed for degeneration of the photoreceptor cell layer alone. All mice were measured at day 3, 7, 14, and 28 after the respective injection of NaIO 3 , MNU or NaCl (control). Fluorescence lifetime imaging was performed using a fluorescence lifetime imaging ophthalmoscope (Heidelberg Engineering, Heidelberg, Germany). Fluorescence was excited at 473 nm and fluorescence lifetimes were measured in a short and a long spectral channel (498-560 nm and 560-720 nm). Corresponding optical coherence tomography (OCT) images were consecutively acquired and histology was performed at the end of the experiments. Segmentation of OCT images and histology verified the cell type-specific degeneration process over time. Retinal autofluorescence lifetimes increased from day 3 to day 28 in mice after NaIO 3 treatment. Finally, at day 28, fluorescence lifetimes were prolonged by 8% in the short and 61% in the long spectral channel compared to control animals (p = 0.21 and p = 0.004, respectively). In mice after MNU treatment, the mean retinal autofluorescence lifetimes were already decreased at day 3 and retinal lifetimes were finally shortened by 27% in the short and 51% in the long spectral channel at day 28 (p = 0.0028). In conclusion, degeneration of the RPE with subsequent photoreceptor degeneration by NaIO 3 lead to longer mean fluorescence lifetimes of the retina compared to control mice, whereas during specific degeneration of the photoreceptor layer induced by MNU shorter lifetimes were measured. Therefore, short retinal fluorescence lifetimes may originate from the RPE and may be modified by the overlaying retinal layers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of Separation Corridors for Visiting Vehicles from the International Space Station

NASA Technical Reports Server (NTRS)

Zaczek, Mariusz P.; Schrock, Rita R.; Schrock, Mark B.; Lowman, Bryan C.

2011-01-01

The International Space Station (ISS) is a very dynamic vehicle with many operational constraints that affect its performance, operations, and vehicle lifetime. Most constraints are designed to alleviate various safety concerns that are a result of dynamic activities between the ISS and various Visiting Vehicles (VVs). One such constraint that has been in place for Russian Vehicle (RV) operations is the limitation placed on Solar Array (SA) positioning in order to prevent collisions during separation and subsequent relative motion of VVs. An unintended consequence of the SA constraint has been the impacts to the operational flexibility of the ISS resulting from the reduced power generation capability as well as from a reduction in the operational lifetime of various SA components. The purpose of this paper is to discuss the technique and the analysis that were applied in order to relax the SA constraints for RV undockings, thereby improving both the ISS operational flexibility and extending its lifetime for many years to come. This analysis focused on the effects of the dynamic motion that occur both prior to and following RV separations. The analysis involved a parametric approach in the conservative application of various initial conditions and assumptions. These included the use of the worst case minimum and maximum vehicle configurations, worst case initial attitudes and attitude rates, and the worst case docking port separation dynamics. Separations were calculated for multiple ISS docking ports, at varied deviations from the nominal undocking attitudes and included the use of two separate attitude control schemes: continuous free-drift and a post separation attitude hold. The analysis required numerical propagation of both the separation motion and the vehicle attitudes using 3-degree-of-freedom (DOF) relative motion equations coupled with rigid body rotational dynamics to generate a large set of separation trajectories.

Improvement in Ge Detector Cooling

DTIC Science & Technology

2008-09-01

RASA) Mark IV, is continually evolving. Cryocooler improvements in recent years have resulted in reduced size, reduced maintenance, improved...lifetime and integrity, improve performance, and resolve the need to procure and handle liquid nitrogen (LN2). Both cryocoolers offer advantages over...interval and lifetime have not yet been determined. Expected lifetimes for both cryocooler units are in excess of 50,000 hours. Both systems will be

An open circuit voltage decay system for performing injection dependent lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Lacouture, Shelby; Schrock, James; Hirsch, Emily; Bayne, Stephen; O'Brien, Heather; Ogunniyi, Aderinto A.

2017-09-01

Of all of the material parameters associated with a semiconductor, the carrier lifetime is by far the most complex and dynamic, being a function of the dominant recombination mechanism, the equilibrium number of carriers, the perturbations in carriers (e.g., carrier injection), and the temperature, to name the most prominent variables. The carrier lifetime is one of the most important parameters in bipolar devices, greatly affecting conductivity modulation, on-state voltage, and reverse recovery. Carrier lifetime is also a useful metric for device fabrication process control and material quality. As it is such a dynamic quantity, carrier lifetime cannot be quoted in a general range such as mobility; it must be measured. The following describes a stand-alone, wide-injection range open circuit voltage decay system with unique lifetime extraction algorithms. The system is initially used along with various lifetime spectroscopy techniques to extract fundamental recombination parameters from a commercial high-voltage PIN diode.

Recoil Distance Method lifetime measurement of the 2 1 + state in 94Sr and implications for the structure of neutron rich Sr isotopes

NASA Astrophysics Data System (ADS)

Chester, Aaron; Starosta, Krzysztof; S1467 Experiment Collaboration

2017-09-01

A high precision lifetime measurement of the 21+ state in 94Sr was performed at TRIUMF's ISAC-II facility by coupling the Recoil Distance Method implemented via the TIGRESS Integrated Plunger with unsafe Coulomb excitation in inverse kinematics. Due to limited statistics imposed by the use of a radioactive 94Sr beam, a likelihood ratio χ2 method was derived and used to compare experimental data to Geant4-simulated lineshapes. The B (E 2 ;21+ ->01+) value extracted from the lifetime measurement of 7 .80-0.40 + 0.50 (stat .) +/- 0.07 (sys .) ps is approximately 25% larger than previously reported while the relative uncertainty has been reduced by a factor of approximately 8. A baseline deformation has been established for Sr isotopes with N <= 58 which is a necessary condition for the Quantum Phase Transition interpretation of the onset of deformation in this region. A summary of the experiment, description of the data analysis methods, and a comparison to existing theoretical models will be presented.

Targeted Victimization and Suicidality Among Trans People: A Web-Based Survey.

PubMed

Zeluf, Galit; Dhejne, Cecilia; Orre, Carolina; Mannheimer, Louise Nilunger; Deogan, Charlotte; Höijer, Jonas; Winzer, Regina; Thorson, Anna Ekéus

2018-04-01

The aim of this study was to investigate the associations between a series of empirically known risk and protective factors and suicidality among trans people in Sweden. Participants were self-selected anonymously to a web-based survey conducted in 2014. Univariable and multivariable logistic regression analyses were performed to assess associations between contributing factors and suicide ideation in the past 12 months and lifetime suicide attempts. The analysis included 796 trans individuals, between 15 and 94 years of age, who live in Sweden. A total of 37% of respondents reported that they have seriously considered suicide during the past 12 months and 32% had ever attempted a suicide. Offensive treatment during the past three months and lifetime exposure to trans-related violence were significantly associated with suicidality. Less satisfaction with contacts with friends and acquaintances and with one's own psychological wellbeing were associated with suicide ideation in the past 12 months. Lack of practical support was associated with lifetime suicide attempts. Our findings show that suicidality is directly correlated with trans-related victimization. Preventing targeted victimization is, therefore, a key preventive intervention against this elevated suicidality.

Nanoporosity studies of novel catalysts through positronium annihilation

NASA Astrophysics Data System (ADS)

Félix, M. V.; Rodríguez-Rojas, R. A.; Castañeda-Contreras, J.; Nava, R.; Consolati, G.; Castaño, V. M.

2006-10-01

Eight novel hybrid silica gel-succinic acid-zinc acetate samples were analyzed through Positron annihilation lifetime spectroscopy in order to study average free volume quantities and free volume distributions. The aim of this work was to understand the type of porosity within these species and its relationship with surface textural properties (tested by the BET method) and catalytic activity. We found a noticeable dependence of o-Ps lifetimes on the nature of each modifier agent (succinic acid, Zn acetate, succinic acid-Zn acetate) fixed on the surface of SiO 2 and SiO 2-Al 2O 3 particles. We observed the trend of the Zinc acetate to create mesopores among silica particles, while succinic acid acts as a positronium quencher and a nanoporosity performer. Long o-Ps lifetimes were decomposed into two components accounting for the existence of interparticle and intraparticle holes, however discrepancies beyond elementary facts between the BET method measurements and our positronium calculations were found. A discussion of the kind of open spaces analysis necessary to fully understand the porosity in these hybrid materials is also presented.

Stress and deformation analysis of double curvature arc dams using finite element method (FEM): A case of budhi gandaki hydropower project

NASA Astrophysics Data System (ADS)

Mishra, Aanand Kumar; Singh, Ajay; Bahadur Singh, Akal

2018-06-01

High rise arc dams are widely used in the development of storage type hydropower project because of the economic advantage. Among different phases considered during the lifetime of dam, control of dam’s safety and performance becomes more concerned during the lifetime. This paper proposed the 3 – D finite element method (FEM) for stress and deformation analysis of double curvature arc dam considering the non – linearity of foundation rock following the Hoek – Brown Criterion. The proposed methodology is implemented through MATLAB scripting language and studied the double curvature arc dam proposed for Budhi Gandaki hydropower project. The stress developed in the foundation rock, compressive and tensile stress acting on the dam are investigated and analysed for the reservoir level variation. Deformation at the top of the dam and in the foundation rock is also investigated. In addition to that, stress and deformation variation in the foundation rock is analysed for various rock properties.

Fluorescence lifetime imaging and Fourier transform infrared spectroscopy of Michelangelo's David.

PubMed

Comelli, Daniela; Valentini, Gianluca; Cubeddu, Rinaldo; Toniolo, Lucia

2005-09-01

We developed a combined procedure for the analysis of works of art based on a portable system for fluorescence imaging integrated with analytical measurements on microsamples. The method allows us to localize and identify organic and inorganic compounds present on the surface of artworks. The fluorescence apparatus measures the temporal and spectral features of the fluorescence emission, excited by ultraviolet (UV) laser pulses. The kinetic of the emission is studied through a fluorescence lifetime imaging system, while an optical multichannel analyzer measures the fluorescence spectra of selected points. The chemical characterization of the compounds present on the artistic surfaces is then performed by means of analytical measurements on microsamples collected with the assistance of the fluorescence maps. The previous concepts have been successfully applied to study the contaminants on the surface of Michelangelo's David. The fluorescence analysis combined with Fourier transform infrared (FT-IR) measurements revealed the presence of beeswax, which permeates most of the statue surface, and calcium oxalate deposits mainly arranged in vertical patterns and related to rain washing.

Experimental investigations, modeling, and analyses of high-temperature devices for space applications: Part 1. Final report, June 1996--December 1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tournier, J.; El-Genk, M.S.; Huang, L.

1999-01-01

The Institute of Space and Nuclear Power Studies at the University of New Mexico has developed a computer simulation of cylindrical geometry alkali metal thermal-to-electric converter cells using a standard Fortran 77 computer code. The objective and use of this code was to compare the experimental measurements with computer simulations, upgrade the model as appropriate, and conduct investigations of various methods to improve the design and performance of the devices for improved efficiency, durability, and longer operational lifetime. The Institute of Space and Nuclear Power Studies participated in vacuum testing of PX series alkali metal thermal-to-electric converter cells and developedmore » the alkali metal thermal-to-electric converter Performance Evaluation and Analysis Model. This computer model consisted of a sodium pressure loss model, a cell electrochemical and electric model, and a radiation/conduction heat transfer model. The code closely predicted the operation and performance of a wide variety of PX series cells which led to suggestions for improvements to both lifetime and performance. The code provides valuable insight into the operation of the cell, predicts parameters of components within the cell, and is a useful tool for predicting both the transient and steady state performance of systems of cells.« less

Experimental investigations, modeling, and analyses of high-temperature devices for space applications: Part 2. Final report, June 1996--December 1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tournier, J.; El-Genk, M.S.; Huang, L.

1999-01-01

The Institute of Space and Nuclear Power Studies at the University of New Mexico has developed a computer simulation of cylindrical geometry alkali metal thermal-to-electric converter cells using a standard Fortran 77 computer code. The objective and use of this code was to compare the experimental measurements with computer simulations, upgrade the model as appropriate, and conduct investigations of various methods to improve the design and performance of the devices for improved efficiency, durability, and longer operational lifetime. The Institute of Space and Nuclear Power Studies participated in vacuum testing of PX series alkali metal thermal-to-electric converter cells and developedmore » the alkali metal thermal-to-electric converter Performance Evaluation and Analysis Model. This computer model consisted of a sodium pressure loss model, a cell electrochemical and electric model, and a radiation/conduction heat transfer model. The code closely predicted the operation and performance of a wide variety of PX series cells which led to suggestions for improvements to both lifetime and performance. The code provides valuable insight into the operation of the cell, predicts parameters of components within the cell, and is a useful tool for predicting both the transient and steady state performance of systems of cells.« less

Bulk lifetime characterization of corona charged silicon wafers with high resistivity by means of microwave detected photoconductivity

NASA Astrophysics Data System (ADS)

Engst, C. R.; Rommel, M.; Bscheid, C.; Eisele, I.; Kutter, C.

2017-12-01

Minority carrier lifetime (lifetime) measurements are performed on corona-charged silicon wafers by means of Microwave Detected Photoconductivity (MDP). The corona charge is deposited on the front and back sides of oxidized wafers in order to adjust accumulation conditions. Once accumulation is established, interface recombination is suppressed and bulk lifetimes are obtained. Neither contacts nor non-CMOS compatible preparation techniques are required in order to achieve accumulation conditions, which makes the method ideally suited for inline characterization. The novel approach, termed ChargedMDP (CMDP), is used to investigate neutron transmutation doped (NTD) float zone silicon with resistivities ranging from 6.0 to 8.2 kΩ cm. The bulk properties of 150 mm NTD wafers are analyzed in detail by performing measurements of the carrier lifetime and the steady-state photoconductivity at various injection levels. The results are compared with MDP measurements of uncharged wafers as well as to the established charged microwave detected Photoconductance Decay (charge-PCD) method. Besides analyzing whole wafers, CMDP measurements are performed on oxide test-structures on a patterned wafer. Finally, the oxide properties are characterized by means of charge-PCD as well as capacitance-voltage measurements. With CMDP, average bulk lifetimes up to 33.1 ms are measured, whereby significant variations are observed among wafers, which are produced out of the same ingot but oxidized in different furnaces. The observed lifetime variations are assumed to be caused by contaminations, which are introduced during the oxidation process. The results obtained by CMDP were neither accessible by means of conventional MDP measurements of uncharged wafers nor with the established charge-PCD method.

Time-Domain Fluorescence Lifetime Imaging Techniques Suitable for Solid-State Imaging Sensor Arrays

PubMed Central

Li, David Day-Uei; Ameer-Beg, Simon; Arlt, Jochen; Tyndall, David; Walker, Richard; Matthews, Daniel R.; Visitkul, Viput; Richardson, Justin; Henderson, Robert K.

2012-01-01

We have successfully demonstrated video-rate CMOS single-photon avalanche diode (SPAD)-based cameras for fluorescence lifetime imaging microscopy (FLIM) by applying innovative FLIM algorithms. We also review and compare several time-domain techniques and solid-state FLIM systems, and adapt the proposed algorithms for massive CMOS SPAD-based arrays and hardware implementations. The theoretical error equations are derived and their performances are demonstrated on the data obtained from 0.13 μm CMOS SPAD arrays and the multiple-decay data obtained from scanning PMT systems. In vivo two photon fluorescence lifetime imaging data of FITC-albumin labeled vasculature of a P22 rat carcinosarcoma (BD9 rat window chamber) are used to test how different algorithms perform on bi-decay data. The proposed techniques are capable of producing lifetime images with enough contrast. PMID:22778606

Utilization of Tabula Rasa to Stabilize Bulk Lifetimes in n-Cz Silicon for High-Performance Solar Cell Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaSalvia, Vincenzo; Jensen, Mallory Ann; Youssef, Amanda

2016-11-21

We investigate a high temperature, high cooling-rate anneal Tabula Rasa (TR) and report its implications on n-type Czochralski-grown silicon (n-Cz Si) for photovoltaic fabrication. Tabula Rasa aims at dissolving and homogenizing oxygen precipitate nuclei that can grow during the cell process steps and degrade the cell performance due to their high internal gettering and recombination activity. The Tabula Rasa thermal treatment is performed in a clean tube furnace with cooling rates >100 degrees C/s. We characterize the bulk lifetime by Sinton lifetime and photoluminescence mapping just after Tabula Rasa, and after the subsequent cell processing. After TR, the bulk lifetimemore » surprisingly degrades to <; 0.1ms, only to recover to values equal or higher than the initial non-treated wafer (several ms), after typical high temperature cell process steps. Those include boron diffusion and oxidation; phosphorus diffusion/oxidation; ambient annealing at 850 degrees C; and crystallization annealing of tunneling-passivating contacts (doped polycrystalline silicon on 1.5 nm thermal oxide). The drastic lifetime improvement during high temperature cell processing is attributed to improved external gettering of metal impurities and annealing of intrinsic point defects. Time and injection dependent lifetime spectroscopy further reveals the mechanisms of lifetime improvement after Tabula Rasa treatment. Additionally, we report the efficacy of Tabula Rasa on n-type Cz-Si wafers and its dependence on oxygen concentration, correlated to position within the ingot.« less

Effect of the microstructure on the lifetime of dental ceramics.

PubMed

Borba, Márcia; de Araújo, Maico D; Fukushima, Karen A; Yoshimura, Humberto N; Cesar, Paulo F; Griggs, Jason A; Della Bona, Alvaro

2011-07-01

To evaluate the effect of the microstructure on the Weibull and slow crack growth (SCG) parameters and on the lifetime of three ceramics used as framework materials for fixed partial dentures (FPDs) (YZ - Vita In-Ceram YZ; IZ - Vita In-Ceram Zirconia; AL - Vita In-Ceram AL) and of two veneering porcelains (VM7 and VM9). Bar-shaped specimens were fabricated according to the manufacturer's instructions. Specimens were tested in three-point flexure in 37°C artificial saliva. Weibull analysis (n=30) and a constant stress-rate test (n=10) were used to determine the Weibull modulus (m) and SCG coefficient (n), respectively. Microstructural and fractographic analyzes were performed using SEM. ANOVA and Tukey's test (α=0.05) were used to statistically analyze data obtained with both microstructural and fractographic analyzes. YZ and AL presented high crystalline content and low porosity (0.1-0.2%). YZ had the highest characteristic strength (σ(0)) value (911MPa) followed by AL (488MPa) and IZ (423MPa). Lower σ(0) values were observed for the porcelains (68-75MPa). Except for IZ and VM7, m values were similar among the ceramic materials. Higher n values were found for YZ (76) and AL (72), followed by IZ (54) and the veneering materials (36-44). Lifetime predictions showed that YZ was the material with the best mechanical performance. The size of the critical flaw was similar among the framework materials (34-48μm) and among the porcelains (75-86μm). The microstructure influenced the mechanical and SCG behavior of the studied materials and, consequently, the lifetime predictions. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

On the impact of multi-axial stress states on trailing edge bondlines in wind turbine rotor blades

NASA Astrophysics Data System (ADS)

Noever Castelos, Pablo; Balzani, Claudio

2016-09-01

For a reliable design of wind turbine systems all of their components have to be designed to withstand the loads appearing in the turbine's lifetime. When performed in an integral manner this is called systems engineering, and is exceptionally important for components that have an impact on the entire wind turbine system, such as the rotor blade. Bondlines are crucial subcomponents of rotor blades, but they are not much recognized in the wind energy research community. However, a bondline failure can lead to the loss of a rotor blade, and potentially of the entire turbine, and is extraordinarily relevant to be treated with strong emphasis when designing a wind turbine. Modern wind turbine rotor blades with lengths of 80 m and more offer a degree of flexibility that has never been seen in wind energy technology before. Large deflections result in high strains in the adhesive connections, especially at the trailing edge. The latest edition of the DNV GL guideline from end of 2015 demands a three-dimensional stress analysis of bondlines, whereas before an isolated shear stress proof was sufficient. In order to quantify the lack of safety from older certification guidelines this paper studies the influence of multi-axial stress states on the ultimate and fatigue load resistance of trailing edge adhesive bonds. For this purpose, detailed finite element simulations of the IWES IWT-7.5-164 reference wind turbine blades are performed. Different yield criteria are evaluated for the prediction of failure and lifetime. The results show that the multi-axial stress state is governed by span-wise normal stresses. Those are evidently not captured in isolated shear stress proofs, yielding non-conservative estimates of lifetime and ultimate load resistance. This finding highlights the importance to include a three-dimensional stress state in the failure analysis of adhesive bonds in modern wind turbine rotor blades, and the necessity to perform a three-dimensional characterization of adhesive materials.

Residual lifetime and 10 year absolute risks of osteoporotic fractures in Chinese men and women.

PubMed

Si, Lei; Winzenberg, Tania M; Chen, Mingsheng; Jiang, Qicheng; Palmer, Andrew J

2015-06-01

To determine the residual lifetime and 10 year absolute risks of osteoporotic fractures in Chinese men and women. A validated state-transition microsimulation model was used. Microsimulation and probabilistic sensitivity analyses were performed to address the uncertainties in the model. All parameters including fracture incidence rates and mortality rates were retrieved from published literature. Simulated subjects were run through the model until they died to estimate the residual lifetime fracture risks. A 10 year time horizon was used to determine the 10 year fracture risks. We estimated the risk of only the first osteoporotic fracture during the simulation time horizon. The residual lifetime and 10 year risks of having the first osteoporotic (hip, clinical vertebral or wrist) fracture for Chinese women aged 50 years were 40.9% (95% CI: 38.3-44.0%) and 8.2% (95% CI: 6.8-9.3%) respectively. For men, the residual lifetime and 10 year fracture risks were 8.7% (95% CI: 7.5-9.8%) and 1.2% (95% CI: 0.8-1.7%) respectively. The residual lifetime fracture risks declined with age, whilst the 10 year fracture risks increased with age until the short-term mortality risks outstripped the fracture risks. Residual lifetime and 10 year clinical vertebral fracture risks were higher than those of hip and wrist fractures in both sexes. More than one third of the Chinese women and approximately one tenth of the Chinese men aged 50 years are expected to sustain a major osteoporotic fracture in their remaining lifetimes. Due to increased fracture risks and a rapidly ageing population, osteoporosis will present a great challenge to the Chinese healthcare system. While national data was used wherever possible, regional Chinese hip and clinical vertebral fracture incidence rates were used, wrist fracture rates were taken from a Norwegian study and calibrated to the Chinese population. Other fracture sites like tibia, humerus, ribs and pelvis were not included in the analysis, thus these risks are likely to be underestimates. Fracture risk factors other than age and sex were not included in the model. Point estimates were used for fracture incidence rates, osteoporosis prevalence and mortality rates for the general population.

Fluorescence lifetime spectroscopy: potential for in-vivo estimation of skin fluorophores changes after low power laser treatment

NASA Astrophysics Data System (ADS)

Ferulova, Inesa; Lihachev, Alexey; Spigulis, Janis

2013-11-01

The impact of visible cwlaser irradiation on skin autofluorescence lifetimes was investigated in spectral range from 450 nm to 600 nm. Skin optical provocations were performed during 1 min by 405 nm low power cw laser with power density up to 20 mW/cm2. Autofluorescence lifetimes were measured before and immediately after the optical provocation.

Benchmarking of Touschek Beam Lifetime Calculations for the Advanced Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, A.; Yang, B.

2017-06-25

Particle loss from Touschek scattering is one of the most significant issues faced by present and future synchrotron light source storage rings. For example, the predicted, Touschek-dominated beam lifetime for the Advanced Photon Source (APS) Upgrade lattice in 48-bunch, 200-mA timing mode is only ~ 2 h. In order to understand the reliability of the predicted lifetime, a series of measurements with various beam parameters was performed on the present APS storage ring. This paper first describes the entire process of beam lifetime measurement, then compares measured lifetime with the calculated one by applying the measured beam parameters. The resultsmore » show very good agreement.« less

Lifetime evaluation of large format CMOS mixed signal infrared devices

NASA Astrophysics Data System (ADS)

Linder, A.; Glines, Eddie

2015-09-01

New large scale foundry processes continue to produce reliable products. These new large scale devices continue to use industry best practice to screen for failure mechanisms and validate their long lifetime. The Failure-in-Time analysis in conjunction with foundry qualification information can be used to evaluate large format device lifetimes. This analysis is a helpful tool when zero failure life tests are typical. The reliability of the device is estimated by applying the failure rate to the use conditions. JEDEC publications continue to be the industry accepted methods.

The impact of lifetime suicidality on academic performance in college freshmen.

PubMed

Mortier, P; Demyttenaere, K; Auerbach, R P; Green, J G; Kessler, R C; Kiekens, G; Nock, M K; Bruffaerts, R

2015-11-01

While suicidal thoughts and behaviors (STB) among college students are common, the associations between STB and academic performance are not well understood. As part of the World Mental Health Surveys International College Student project, web-based self-reported STB of KU Leuven (Leuven, Belgium) incoming freshmen (N=4921; response rate=65.4%) was collected, as well as academic year percentage (AYP), and the departments to which students belong. Single- and multilevel multivariate analyses were conducted, adjusted for gender, age, parental educational level, and comorbid lifetime emotional problems. Lifetime suicide plan and attempt upon college entrance were associated with significant decreases in AYP (3.6% and 7.9%, respectively). A significant interaction was found with average departmental AYP, with STB more strongly associated with reduced AYP in departments with lower than higher average AYP. Limited sample size precluded further investigation of interactions between department-level and student-level variables. No information was available on freshman secondary school academic performance. Lifetime STB has a strong negative association with academic performance in college. Our study suggests a potential role for the college environment as target for treatment and prevention interventions. Copyright © 2015 Elsevier B.V. All rights reserved.

Lifetime cost of everolimus vs axitinib in patients with advanced renal cell carcinoma who failed prior sunitinib therapy in the US.

PubMed

Perrin, Allison; Sherman, Steven; Pal, Sumanta; Chua, Andrew; Gorritz, Magdaliz; Liu, Zhimei; Wang, Xufang; Culver, Kenneth; Casciano, Roman; Garrison, Louis P

2015-03-01

Everolimus and axitinib are approved in the US to treat patients with advanced renal cell carcinoma (RCC) after failure on sunitinib or sorafenib, and one prior systemic therapy (e.g., sunitinib), respectively. Two indirect comparisons performed to evaluate progression-free survival in patients treated with everolimus vs axitinib suggested similar efficacy between the two treatments. Therefore, this analysis compares the lifetime costs of these two therapies among sunitinib-refractory advanced RCC patients from a US payer perspective. A Markov model was developed to simulate a cohort of sunitinib-refractory advanced RCC patients and estimate the cost of treating patients with everolimus vs axitinib. The following health states were included: stable disease without adverse events (AEs), stable disease with AEs, disease progression (PD), and death. The model included the following resources: active treatments, post-progression treatments, adverse events, physician and nurse visits, scans and tests, and palliative care. Resource utilization inputs were derived from a US claims database analysis. Additionally, a 3% annual discount rate was applied to costs, and the robustness of the model results was tested by conducting sensitivity analyses, including those on dosing scheme and post-progression treatment costs. Base case results demonstrated that patients treated with everolimus cost an average of $12,985 (11%) less over their lifetimes than patients treated with axitinib. The primary difference in costs was related to active treatment, which was largely driven by axitinib's higher dose intensity. RESULTS remained consistent across sensitivity analyses for AE and PD treatment costs, as well as dose intensity and discount rates. The results suggest that everolimus likely leads to lower lifetime costs than axitinib for sunitinib-refractory advanced RCC patients in the US.

In-Situ Measurement of Hall Thruster Erosion Using a Fiber Optic Regression Probe

NASA Technical Reports Server (NTRS)

Polzink, Kurt A.; Korman, Valentin

2008-01-01

One potential life-limiting mechanism in a Hall thruster is the erosion of the ceramic material comprising the discharge channel. This is especially true for missions that require long thrusting periods and can be problematic for lifetime qualification, especially when attempting to qualify a thruster by analysis rather than a test lasting the full duration of the mission. In addition to lifetime, several analytical and numerical models include electrode erosion as a mechanism contributing to enhanced transport properties. However, there is still a great deal of dispute over the importance of erosion to transport in Hall thrusters. The capability to perform an in-situ measurement of discharge channel erosion is useful in addressing both the lifetime and transport concerns. An in-situ measurement would allow for real-time data regarding the erosion rates at different operating points, providing a quick method for empirically anchoring any analysis geared towards lifetime qualification. Erosion rate data over a thruster's operating envelope would also be useful in the modeling of the detailed physics inside the discharge chamber. A recent fundamental sensor development effort has led to a novel regression, erosion, and ablation sensor technology (REAST). The REAST sensor allows for measurement of real-time surface erosion rates at a discrete surface location. The sensor was tested using a linear Hall thruster geometry, which served as a means of producing plasma erosion of a ceramic discharge chamber. The mass flow rate, discharge voltage, and applied magnetic field strength could be varied, allowing for erosion measurements over a broad thruster operating envelope. Results are presented demonstrating the ability of the REAST sensor to capture not only the insulator erosion rates but also changes in these rates as a function of the discharge parameters.

Investigation of Fluorescence Lifetime Quenching of Ru(bpy)[subscript 3][superscript 2+] by Oxygen Using a Pulsed Light-Emitting Diode

ERIC Educational Resources Information Center

Rusak, David A.; James, William H., III; Ferzola, Maria J.; Stefanski, Michael J.

2006-01-01

An experiment related to the measurement of fluorescence lifetime for an undergraduate instrumental analysis or physical chemistry laboratory that highlights relative rates of electronic transitions in molecules and introduces students to data collection of a pulsed signal is illustrated. The experiment of the long fluorescence lifetime of…

Device performance and lifetime of polymer:fullerene solar cells with UV-ozone-irradiated hole-collecting buffer layers.

PubMed

Lee, Seungsoo; Nam, Sungho; Lee, Hyena; Kim, Hwajeong; Kim, Youngkyoo

2011-11-18

We report the influence of UV-ozone irradiation of the hole-collecting buffer layers on the performance and lifetime of polymer:fullerene solar cells. UV-ozone irradiation was targeted at the surface of the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) layers by varying the irradiation time up to 600 s. The change of the surface characteristics in the PEDOT:PSS after UV-ozone irradiation was measured by employing optical absorption spectroscopy, photoelectron yield spectroscopy, and contact angle measurements, while Raman and X-ray photoelectron spectroscopy techniques were introduced for more microscopic analysis. Results showed that the UV-ozone irradiation changed the chemical structure/composition of the surface of the PEDOT:PSS layers leading to the gradual increase of ionization potential with irradiation time in the presence of up-and-down variations in the contact angle (polarity). This surface property change was attributed to the formation of oxidative components, as evidenced by XPS and Auger electron images, which affected the sheet resistance of the PEDOT:PSS layers. Interestingly, device performance was slightly improved by short irradiation (up to 10 s), whereas it was gradually decreased by further irradiation. The short-duration illumination test showed that the lifetime of solar cells with the UV-ozone irradiated PEDOT:PSS layer was improved due to the protective role of the oxidative components formed upon UV-ozone irradiation against the attack of sulfonic acid groups in the PEDOT:PSS layer to the active layer. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PbCl2-tuned inorganic cubic CsPbBr3(Cl) perovskite solar cells with enhanced electron lifetime, diffusion length and photovoltaic performance

NASA Astrophysics Data System (ADS)

Li, Bo; Zhang, Yanan; Zhang, Luyuan; Yin, Longwei

2017-08-01

Inorganic CsPbBr3 perovskite is arousing great interest following after organic-inorganic hybrid halide perovskites, and is found as a good candidate for photovoltaic devices for its prominent photoelectric property and stability. Herein, we for the first time report on PbCl2-tuned inorganic Cl-doped CsPbBr3(Cl) perovskite solar cells with adjustable crystal structure and Cl doping for enhanced carrier lifetime, extraction rate and photovoltaic performance. The effect of PbCl2 on the morphologies, structures, optical, and photovoltaic performance of CsPbBr3 perovskite solar cells is investigated systemically. Compared with orthorhombic CsPbBr3, cubic CsPbBr3 demonstrates a significant improvement for electron lifetime (from 6.7 ns to 12.3 ns) and diffusion length (from 69 nm to 197 nm), as well as the enhanced electron extraction rate from CsPbBr3 to TiO2. More importantly, Cl doping benefits the further enhancement of carrier lifetime (14.3 ns) and diffusion length (208 nm). The Cl doped cubic CsPbBr3(Cl) perovskite solar cell exhibits a Jsc of 8.47 mA cm-2 and a PCE of 6.21%, superior to that of pure orthorhombic CsPbBr3 (6.22 mA cm-2 and 3.78%). The improvement of photovoltaic performance can be attributed to enhanced carrier lifetime, diffusion length and extraction rates, as well as suppressed nonradiative recombination.

The Effect of Upscaling and Performance Degradation on Onshore Wind Turbine Lifetime Extension Decision Making

NASA Astrophysics Data System (ADS)

Rubert, T.; McMillan, D.; Niewczas, P.

2017-11-01

Ever greater rated wind turbine generators (WTGs) are reaching their end of design life in the near future. In addition, first research approaches quantified the impact of long-term performance degradation of WTGs. As a consequence, this work is aimed at discussing and analysing the impact of upscaling and performance degradation on the economics of wind turbine lifetime extension. Findings reveal that the lifetime extension levelised cost of energy (LCOE2) of an 18 MW wind farm comprising of 0.5 MW rated WTGs are within the order of £23.52 per MWh. Alternatively, if the same wind farm consists of fewer 2 or 3 MW WTGs, the LCOE2 reduces to £16.56 or £15.49 per MWh, respectively. Further, findings reveal that an annual performance degradation of 1.6% (0.2%) increases LCOE2 by 34-41% (3.6-4.3%).

Cost-effectiveness analysis of quadrivalent influenza vaccination in at-risk adults and the elderly: an updated analysis in the U.K.

PubMed

Meier, G; Gregg, M; Poulsen Nautrup, B

2015-01-01

To update an earlier evaluation estimating the cost-effectiveness of quadrivalent influenza vaccination (QIV) compared with trivalent influenza vaccination (TIV) in the adult population currently recommended for influenza vaccination in the UK (all people aged ≥65 years and people aged 18-64 years with clinical risk conditions). This analysis takes into account updated vaccine prices, reference costs, influenza strain circulation, and burden of illness data. A lifetime, multi-cohort, static Markov model was constructed with seven age groups. The model was run in 1-year cycles for a lifetime, i.e., until the youngest patients at entry reached the age of 100 years. The base-case analysis was from the perspective of the UK National Health Service, with a secondary analysis from the societal perspective. Costs and benefits were discounted at 3.5%. Herd effects were not included. Inputs were derived from systematic reviews, peer-reviewed articles, and government publications and databases. One-way and probabilistic sensitivity analyses were performed. In the base-case, QIV would be expected to avoid 1,413,392 influenza cases, 41,780 hospitalizations, and 19,906 deaths over the lifetime horizon, compared with TIV. The estimated incremental cost-effectiveness ratio (ICER) was £14,645 per quality-adjusted life-year (QALY) gained. From the societal perspective, the estimated ICER was £13,497/QALY. A strategy of vaccinating only people aged ≥65 years had an estimated ICER of £11,998/QALY. Sensitivity analysis indicated that only two parameters, seasonal variation in influenza B matching and influenza A circulation, had a substantial effect on the ICER. QIV would be likely to be cost-effective compared with TIV in 68% of simulations with a willingness-to-pay threshold of <£20,000/QALY and 87% with a willingness-to-pay threshold of <£30,000/QALY. In this updated analysis, QIV was estimated to be cost-effective compared with TIV in the U.K.

Lifetime physical activity and female stress urinary incontinence.

PubMed

Nygaard, Ingrid E; Shaw, Janet M; Bardsley, Tyler; Egger, Marlene J

2015-07-01

We sought to estimate whether moderate/severe stress urinary incontinence (SUI) in middle-aged women is associated with overall lifetime physical activity (including leisure, household, outdoor, and occupational), as well as lifetime leisure (recreational), lifetime strenuous, and strenuous activity during the teen years. Recruitment for this case-control study was conducted in primary-care-level family medicine and gynecology clinics. A total of 1538 enrolled women ages 39-65 years underwent a Pelvic Organ Prolapse Quantification examination to assess vaginal support. Based on Incontinence Severity Index scores, cases had moderate/severe and controls had no/mild SUI. We excluded 349 with vaginal descent at/below the hymen (pelvic organ prolapse), 194 who did not return questionnaires, and 110 with insufficient activity data for analysis. In all, 213 cases were frequency matched 1:1 by age group to controls. Physical activity was measured using the Lifetime Physical Activity Questionnaire, in which women recall activity from menarche to present. We created separate multivariable logistic regression models for activity measures. SUI odds increased slightly with overall lifetime activity (odds ratio [OR], 1.20 per 70 additional metabolic equivalent of task-h/wk; 95% confidence interval [CI], 1.02-1.41), and were not associated with lifetime strenuous activity (OR, 1.11; 95% CI, 0.99-1.25). In quintile analysis of lifetime leisure activity, which demonstrated a nonlinear pattern, all quintiles incurred about half the odds of SUI compared to reference (second quintile; P = .009). Greater strenuous activity in teen years modestly increased SUI odds (OR, 1.37 per 7 additional h/wk; 95% CI, 1.09-1.71); OR, 1.75; 95% CI, 1.15-2.66 in sensitivity analysis adjusting for measurement error. The predicted probability of SUI rose linearly in women exceeding 7.5 hours of strenuous activity/wk during teen years. Teen strenuous activity had a similar effect on SUI odds when adjusted for subsequent strenuous activity during ages 21-65 years. In middle-aged women, a slight increased odds of SUI was noted only after substantially increased overall lifetime physical activity. Increased lifetime leisure activity decreased and lifetime strenuous activity appeared unrelated to SUI odds. Greater strenuous activity during teen years modestly increased SUI odds. Copyright © 2015 Elsevier Inc. All rights reserved.

SIRTF thermal design modifications to increase lifetime

NASA Astrophysics Data System (ADS)

Petrick, S. W.

1993-01-01

An effort was made to increase the predicted lifetime of the SIRTF dewar by lowering the exterior shell temperature, increasing the radiated energy from the vapor cooled shields and reconfiguring the vapor cooled shields. The lifetime increases can be used to increase the scientific return from the mission and as a trade-off against mass and cost. This paper describes the configurations studied, the steady state thermal model used, the analytical methods and the results of the analysis. Much of the heat input to the outside dewar shell is radiative heat transfer from the solar panel. To lower the shell temperature, radiative cooled shields were placed between the solar panel and the dewar shell and between the bus and the dewar shell. Analysis showed that placing a radiator on the outer vapor cooled shield had a significant effect on lifetime. Lengthening the distance between the outer shell and the point where the vapor cooled shields are attached to the support straps also improved lifetime.

Sun Series program for the REEDA System. [predicting orbital lifetime using sunspot values

NASA Technical Reports Server (NTRS)

Shankle, R. W.

1980-01-01

Modifications made to data bases and to four programs in a series of computer programs (Sun Series) which run on the REEDA HP minicomputer system to aid NASA's solar activity predictions used in orbital life time predictions are described. These programs utilize various mathematical smoothing technique and perform statistical and graphical analysis of various solar activity data bases residing on the REEDA System.

Strength and reliability analysis of metal-composite overwrapped pressure vessel

NASA Astrophysics Data System (ADS)

Burov, A. E.; Lepikhin, A. M.; Moskvichev, V. V.

2017-12-01

Metal-composite overwrapped pressure vessels (MCOPV) have found a wide application in aerospace and aeronautical industries. Such vessels should combine impermeability and high weight efficiency with enhanced long-term safety and durability. To meet these requirements, theoretical and experimental studies on the mechanics of deformation and failure of MCOPV are required. In the paper, the analysis on strength, lifetime and reliability of MCOPV is presented. A high performance of the MCOPV is justified by comparing the calculation results with experiment data obtained on full-scale samples.

Nondestructive monitoring of fatigue damage evolution in austenitic stainless steel by positron-lifetime measurements

NASA Astrophysics Data System (ADS)

Holzwarth, Uwe; Schaaff, Petra

2004-03-01

Positron-lifetime measurements have been performed on austenitic stainless steel during (i) stress- and (ii) strain-controlled fatigue experiments for different applied stress and strain amplitudes, respectively. For this purpose a generator-detector assembly with a 72Se/72As positron generator [maximum activity 25 μCi (0.9 MBq)] has been mounted on mechanical testing machines in order to measure the positron lifetime without removing the specimens from the load train. The average positron lifetime has been determined by a β+-γ coincidence. The feasibility to use the average positron lifetime for monitoring the evolution of fatigue damage and to predict early failure has been examined. In strain- and stress-controlled experiments the average positron lifetime shows a pronounced increase within the first 10% and 40% of the fatigue life, respectively. In stress-controlled experiments the average positron lifetime at failure depends significantly on the applied stress amplitude. In strain-controlled experiments significantly different positron lifetimes for different applied plastic strain amplitudes are obtained within the first 1.000 fatigue cycles, whereas differences get wiped out during further cycling until failure.

Non-invasive imaging of skin cancer with fluorescence lifetime imaging using two photon tomography

NASA Astrophysics Data System (ADS)

Patalay, Rakesh; Talbot, Clifford; Alexandrov, Yuriy; Munro, Ian; Breunig, Hans Georg; König, Karsten; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Christopher

2011-07-01

Multispectral fluorescence lifetime imaging (FLIM) using two photon microscopy as a non-invasive technique for the diagnosis of skin lesions is described. Skin contains fluorophores including elastin, keratin, collagen, FAD and NADH. This endogenous contrast allows tissue to be imaged without the addition of exogenous agents and allows the in vivo state of cells and tissues to be studied. A modified DermaInspect® multiphoton tomography system was used to excite autofluorescence at 760 nm in vivo and on freshly excised ex vivo tissue. This instrument simultaneously acquires fluorescence lifetime images in four spectral channels between 360-655 nm using time-correlated single photon counting and can also provide hyperspectral images. The multispectral fluorescence lifetime images were spatially segmented and binned to determine lifetimes for each cell by fitting to a double exponential lifetime model. A comparative analysis between the cellular lifetimes from different diagnoses demonstrates significant diagnostic potential.

Memory performance in abstinent 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") users.

PubMed

Groth-Marnat, Gary; Howchar, Hennedy; Marsh, Ali

2007-02-01

Research with animals and humans has suggested that acute and subacute use of 3,4-methylenedioxymethamphetamine (MDMA "ecstasy") may lead to memory impairment. However, research is limited by (1) low power due to small sample sizes, (2) the possible confound of polydrug use, and (3) the failure to consider intelligence as a covariate. The present study compared the memory performance on the Wechsler Memory Scale-III of 26 abstinent (2-wk. minimum) recreational MDMA users with 26 abstinent (2-wk. minimum) recreational polydrug users. Despite significantly greater polydrug use amongst these MDMA users, no significant group differences in memory were observed. Regression of total lifetime amount of MDMA use also did not predict memory performance after accounting for intelligence. In addition, the length of time since abstinence (at least 2 wk.) was not associated with an increase in memory performance. Greater total lifetime cocaine use, rather than total lifetime MDMA use, was significantly associated with greater decrements in General Memory and Delayed Verbal Memory performance.

A multiple-cathode, high-power, rectangular ion thruster discharge chamber of increasing thruster lifetime

NASA Astrophysics Data System (ADS)

Rovey, Joshua Lucas

Ion thrusters are high-efficiency, high-specific impulse space propulsion systems proposed for deep space missions requiring thruster operational lifetimes of 7--14 years. One of the primary ion thruster components is the discharge cathode assembly (DCA). The DCA initiates and sustains ion thruster operation. Contemporary ion thrusters utilize one molybdenum keeper DCA that lasts only ˜30,000 hours (˜3 years), so single-DCA ion thrusters are incapable of satisfying the mission requirements. The aim of this work is to develop an ion thruster that sequentially operates multiple DCAs to increase thruster lifetime. If a single-DCA ion thruster can operate 3 years, then perhaps a triple-DCA thruster can operate 9 years. Initially, a multiple-cathode discharge chamber (MCDC) is designed and fabricated. Performance curves and grid-plane current uniformity indicate operation similar to other thrusters. Specifically, the configuration that balances both performance and uniformity provides a production cost of 194 W/A at 89% propellant efficiency with a flatness parameter of 0.55. One of the primary MCDC concerns is the effect an operating DCA has on the two dormant cathodes. Multiple experiments are conducted to determine plasma properties throughout the MCDC and near the dormant cathodes, including using "dummy" cathodes outfitted with plasma diagnostics and internal plasma property mapping. Results are utilized in an erosion analysis that suggests dormant cathodes suffer a maximum pre-operation erosion rate of 5--15 mum/khr (active DCA maximum erosion is 70 mum/khr). Lifetime predictions indicate that triple-DCA MCDC lifetime is approximately 2.5 times longer than a single-DCA thruster. Also, utilization of new keeper materials, such as carbon graphite, may significantly decrease both active and dormant cathode erosion, leading to a further increase in thruster lifetime. Finally, a theory based on the near-DCA plasma potential structure and propellant flow rate effects is developed to explain active DCA erosion. The near-DCA electric field pulls ions into the DCA such that they bombard and erode the keeper. Charge-exchange collisions between bombarding ions and DCA-expelled neutral atoms reduce erosion. The theory explains ion thruster long-duration wear-test results and suggests increasing propellant flow rate may eliminate or reduce DCA erosion.

AYUSH: A Technique for Extending Lifetime of SRAM-NVM Hybrid Caches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mittal, Sparsh; Vetter, Jeffrey S

2014-01-01

Recently, researchers have explored way-based hybrid SRAM-NVM (non-volatile memory) last level caches (LLCs) to bring the best of SRAM and NVM together. However, the limited write endurance of NVMs restricts the lifetime of these hybrid caches. We present AYUSH, a technique to enhance the lifetime of hybrid caches, which works by using data-migration to preferentially use SRAM for storing frequently-reused data. Microarchitectural simulations confirm that AYUSH achieves larger improvement in lifetime than a previous technique and also maintains performance and energy efficiency. For single, dual and quad-core workloads, the average increase in cache lifetime with AYUSH is 6.90X, 24.06X andmore » 47.62X, respectively.« less

Positron annihilation lifetime spectroscopy study of Kapton thin foils

NASA Astrophysics Data System (ADS)

Kanda, G. S.; Ravelli, L.; Löwe, B.; Egger, W.; Keeble, D. J.

2016-01-01

Variable energy positron annihilation lifetime spectroscopy (VE-PALS) experiments on polyimide material Kapton are reported. Thin Kapton foils are widely used in a variety of mechanical, electronic applications. PALS provides a sensitive probe of vacancy-related defects in a wide range of materials, including open volume in polymers. Varying the positron implantation energy enables direct measurement of thin foils. Thin Kapton foils are also commonly used to enclose the positron source material in conventional PALS measurements performed with unmoderated radionuclide sources. The results of depth-profiled positron lifetime measurements on 7.6 μm and 25 μm Kapton foils are reported and determine a dominant 385(1) ps lifetime component. The absence of significant nanosecond lifetime component due to positronium formation is confirmed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, John B.; Detsi, Eric; Liu, Yijin

Next generation Li-ion batteries will require negative electrode materials with energy densities many-fold higher than that found in the graphitic carbon currently used in commercial Li-ion batteries. While various nanostructured alloying-type anode materials may satisfy that requirement, such materials do not always exhibit long cycle lifetimes and/or their processing routes are not always suitable for large-scale synthesis. Here, we report on a high-performance anode material for next generation Li-ion batteries made of nanoporous Sn powders with hierarchical ligament morphology. This material system combines both long cycle lifetimes (more than 72% capacity retention after 350 cycles), high capacity (693 mAh/g, nearlymore » twice that of commercial graphitic carbon), good charging/discharging capabilities (545 mAh/g at 1 A/g, 1.5C), and a scalable processing route that involves selective alloy corrosion. The good cycling performance of this system is attributed to its nanoporous architecture and its unique hierarchical ligament morphology, which accommodates the large volume changes taking place during lithiation, as confirmed by synchrotron-based ex-situ X-ray 3D tomography analysis. In conclusion, our findings are an important step for the development of high-performance Li-ion batteries.« less

Influence of temperature on the aging behavior of 18650-type lithium ion cells: A comprehensive approach combining electrochemical characterization and post-mortem analysis

NASA Astrophysics Data System (ADS)

Friesen, Alex; Mönnighoff, Xaver; Börner, Markus; Haetge, Jan; Schappacher, Falko M.; Winter, Martin

2017-02-01

The understanding of the aging behavior of lithium ion batteries in automotive and energy storage applications is essential for the acceptance of the technology. Therefore, aging experiments were conducted on commercial 18650-type state-of-the-art cells to determine the influence of the temperature during electrochemical cycling on the aging behavior of the different cell components. The cells, based on Li(Ni0.5Co0.2Mn0.3)O2 (NCM532)/graphite, were aged at 20 °C and 45 °C to different states of health. The electrochemical performance of the investigated cells shows remarkable differences depending on the cycling temperature. At contrast to the expected behavior, the cells cycled at 45 °C show a better electrochemical performance over lifetime than the cells cycled at 20 °C. Comprehensive post-mortem analyses revealed the main aging mechanisms, showing a complex interaction between electrodes and electrolyte. The main aging mechanisms of the cells cycled at 45 °C differ strongly at contrast to cells cycled at 20 °C. A strong correlation between the formed SEI, the electrolyte composition and the electrochemical performance over lifetime was observed.

Optical damage performance of conductive widegap semiconductors: spatial, temporal, and lifetime modeling

DOE PAGES

Elhadj, Selim; Yoo, Jae-hyuck; Negres, Raluca A.; ...

2016-12-19

The optical damage performance of electrically conductive gallium nitride (GaN) and indium tin oxide (ITO) films is addressed using large area, high power laser beam exposures at 1064 nm sub-bandgap wavelength. Analysis of the laser damage process assumes that onset of damage (threshold) is determined by the absorption and heating of a nanoscale region of a characteristic size reaching a critical temperature. We use this model to rationalize semi-quantitatively the pulse width scaling of the damage threshold from picosecond to nanosecond timescales, along with the pulse width dependence of the damage threshold probability derived by fitting large beam damage densitymore » data. Multi-shot exposures were used to address lifetime performance degradation described by an empirical expression based on the single exposure damage model. A damage threshold degradation of at least 50% was observed for both materials. Overall, the GaN films tested had 5-10 × higher optical damage thresholds than the ITO films tested for comparable transmission and electrical conductivity. This route to optically robust, large aperture transparent electrodes and power optoelectronics may thus involve use of next generation widegap semiconductors such as GaN.« less

Lifetime Segmented Assimilation Trajectories and Health Outcomes in Latino and Other Community Residents

PubMed Central

Marsiglia, Flavio F.; Kulis, Stephen; Kellison, Joshua G.

2010-01-01

Objectives. Under an ecodevelopmental framework, we examined lifetime segmented assimilation trajectories (diverging assimilation pathways influenced by prior life conditions) and related them to quality-of-life indicators in a diverse sample of 258 men in the Pheonix, AZ, metropolitan area. Methods. We used a growth mixture model analysis of lifetime changes in socioeconomic status, and used acculturation to identify distinct lifetime segmented assimilation trajectory groups, which we compared on life satisfaction, exercise, and dietary behaviors. We hypothesized that lifetime assimilation change toward mainstream American culture (upward assimilation) would be associated with favorable health outcomes, and downward assimilation change with unfavorable health outcomes. Results. A growth mixture model latent class analysis identified 4 distinct assimilation trajectory groups. In partial support of the study hypotheses, the extreme upward assimilation trajectory group (the most successful of the assimilation pathways) exhibited the highest life satisfaction and the lowest frequency of unhealthy food consumption. Conclusions. Upward segmented assimilation is associated in adulthood with certain positive health outcomes. This may be the first study to model upward and downward lifetime segmented assimilation trajectories, and to associate these with life satisfaction, exercise, and dietary behaviors. PMID:20167890

Mid-Infrared Lifetime Imaging for Viability Evaluation of Lettuce Seeds Based on Time-Dependent Thermal Decay Characterization

PubMed Central

Kim, Ghiseok; Kim, Geon Hee; Ahn, Chi-Kook; Yoo, Yoonkyu; Cho, Byoung-Kwan

2013-01-01

An infrared lifetime thermal imaging technique for the measurement of lettuce seed viability was evaluated. Thermal emission signals from mid-infrared images of healthy seeds and seeds aged for 24, 48, and 72 h were obtained and reconstructed using regression analysis. The emission signals were fitted with a two-term exponential model that had two amplitudes and two time variables as lifetime parameters. The lifetime thermal decay parameters were significantly different for seeds with different aging times. Single-seed viability was visualized using thermal lifetime images constructed from the calculated lifetime parameter values. The time-dependent thermal signal decay characteristics, along with the decay amplitude and delay time images, can be used to distinguish aged lettuce seeds from normal seeds. PMID:23529120

Determination of minority-carrier lifetime and surface recombination velocity with high spacial resolution

NASA Technical Reports Server (NTRS)

Watanabe, M.; Actor, G.; Gatos, H. C.

1977-01-01

Quantitative analysis of the electron beam induced current in conjunction with high-resolution scanning makes it possible to evaluate the minority-carrier lifetime three dimensionally in the bulk and the surface recombination velocity two dimensionally, with a high spacial resolution. The analysis is based on the concept of the effective excitation strength of the carriers which takes into consideration all possible recombination sources. Two-dimensional mapping of the surface recombination velocity of phosphorus-diffused silicon diodes is presented as well as a three-dimensional mapping of the changes in the minority-carrier lifetime in ion-implanted silicon.

Development of a Time Domain Fluorimeter for Fluorescent Lifetime Multiplexing Analysis

PubMed Central

Weissleder, Ralph; Mahmood, Umar

2009-01-01

We show that a portable, inexpensive USB-powered time domain fluorimeter (TDF) and analysis scheme were developed for use in evaluating a new class of fluorescent lifetime multiplexed dyes. Fluorescent proteins, organic dyes, and quantum dots allow the labeling of more and more individual features within biological systems, but the wide absorption and emission spectra of these fluorophores limit the number of distinct processes which may be simultaneously imaged using spectral separation alone. By additionally separating reporters in a second dimension, fluorescent lifetime multiplexing provides a means to multiply the number of available imaging channels. PMID:19830273

Sensitivity to neutrino decay with atmospheric neutrinos at the INO-ICAL detector

NASA Astrophysics Data System (ADS)

Choubey, Sandhya; Goswami, Srubabati; Gupta, Chandan; Lakshmi, S. M.; Thakore, Tarak

2018-02-01

Sensitivity of the magnetized Iron Calorimeter (ICAL) detector at the proposed India-based Neutrino Observatory (INO) to invisible decay of the mass eigenstate ν3 using atmospheric neutrinos is explored. A full three-generation analysis including Earth matter effects is performed in a framework with both decay and oscillations. The wide energy range and baselines offered by atmospheric neutrinos are shown to be excellent for constraining the ν3 lifetime. We find that with an exposure of 500 kton -yr the ICAL atmospheric experiment could constrain the ν3 lifetime to τ3/m3>1.51 ×10-10 s /eV at the 90% C.L. This is 2 orders of magnitude tighter than the bound from MINOS. The effect of invisible decay on the precision measurement of θ23 and |Δ m322| is also studied.

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Kinomura, A.; Suzuki, R.; Oshima, N.; O'Rourke, B. E.; Nishijima, T.; Ogawa, H.

2014-12-01

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at a pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO2 layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.

Experimental radiative lifetimes, branching fractions, and oscillator strengths of some levels in Tm III

NASA Astrophysics Data System (ADS)

Yu, Qi; Wang, Xinghao; Li, Qiu; Gong, Yimin; Dai, Zhenwen

2018-06-01

Natural radiative lifetimes for five even-parity levels of Tm III were measured by time-resolved laser-induced fluorescence method. The branching fraction measurements were performed based on the emission spectra of a hollow cathode lamp. By combining the measured branching fractions and the lifetime values reported in this work and in literature, experimental transition probabilities and oscillator strengths for 11 transitions were derived for the first time.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lea, C.S.; Selvin, S.; Buffler, P.A.

This pilot study uses a unique method to calculate cumulative lifetime exposure to, ultraviolet radiation-b to determine if this refined method would indicate differences in lifetime cumulative UVB exposure between age and sex matched controls. Forty-four age and sex matched cases and controls demonstrated no significant difference in mean cumulative lifetime UVB exposure based on the duration and location of residence. This pilot study suggests that further analysis of the dataset should be conducted to determine if the cumulative lifetime exposure hypothesis is of primary importance regarding the association between UVB exposure and development of cutaneous malignant melanoma.

Lifetime Physical Activity and Breast Cancer: a Case-Control Study in Kelantan, Malaysia.

PubMed

Yen, Siew Hwa; Knight, A; Krishna, Mbv; Muda, Wmw; Rufai, Aa

2016-01-01

Physical inactivity has been identified as the fourth leading risk factor for global mortality and is associated with increased breast cancer diagnosis and recurrence. To examine the association between adult lifetime physical activity and breast cancer risk in a case-control analysis. This study involved 122 cases of breast cancer and 121 controls in the state of Kelantan in Malaysia. A comprehensive measure of lifetime physical activity was used to assess occupational, household, and recreational/sports activity. For every type of activity, a metabolic equivalent (MET) score was assigned using the compendium of physical activities. MET-hours/week per year for all types of activities at different levels of intensities for different age groups were calculated. Logistic regression analysis was used to estimate odds ratios between various measures of physical activity and breast cancer risk. The mean MET-hours/week per year for all activities were 120.0 and 132.9 of MET-hours/week per year for cases and controls respectively. Household activities accounted for about 70% of the total lifetime physical activities. Only about 2.5% of the total lifetime physical activities were in the form of recreational/sports. This study found no association between lifetime occupational and recreational/sports physical activities with breast cancer risk among Kelantanese women. However, higher intensity lifetime household activities seemed to significantly reduce risk of breast cancer.

Performance degradation of space Stirling cryocoolers due to gas contamination

NASA Astrophysics Data System (ADS)

Liu, Xin-guang; Wu, Yi-nong; Yang, Shao-hua; Zhang, Xiao-ming; Lu, Guo-hua; Zhang, Li

2011-08-01

With extensive application of infrared detective techniques, Stirling cryocoolers, used as an active cooling source, have been developed vigorously in China. After the cooler's cooling performance can satisfy the mission's request, its reliability level is crucial for its application. Among all the possible failure mechanisms, gas contamination has been found to be the most notorious cause of cooler's performance degradation by failure analyses. To analyze the characteristic of gas contamination, some experiments were designed and carried out to quantitatively analyze the relationship between failure and performance. Combined with the test results and the outgassing characteristic of non-metal materials in the cryocooler, a degradation model of cooling performance was given by T(t)=T0+A[1-exp(-t/B)] under some assumptions, where t is the running time, T is the Kelvin cooling temperature, and T0, A, B are model parameters, which can be given by the least square method. Here T0 is the fitting initial cooling temperature, A is the maximum range of performance degradation, and B is the time dependent constant of degradation. But the model parameters vary when a cryocooler is running at different cooling temperature ranges, or it is treated by different cleaning process. In order to verify the applicability of the degradation model, data fit analysis on eight groups of cooler's lifetime test was carried out. The final work indicated this model fit well with the performance degradation of space Stirling cryocoolers due to gas contamination and this model could be used to predict or evaluation the cooler's lifetime. Gaseous contamination will not arouse severe performance degradation until the contaminants accumulate to a certain amount, but it could be fatal when it works. So it is more serious to the coolers whose lifetime is more than 10,000 h. The measures taken to control or minimize its damage were discussed as well. To the long-life cryocooler, internal materials must be baked and organic/epoxy materials should be used as few as possible. Further more, pipeline for filling working fluid must have purifying facilities.

Polar plot representation of time-resolved fluorescence.

PubMed

Eichorst, John Paul; Wen Teng, Kai; Clegg, Robert M

2014-01-01

Measuring changes in a molecule's fluorescence emission is a common technique to study complex biological systems such as cells and tissues. Although the steady-state fluorescence intensity is frequently used, measuring the average amount of time that a molecule spends in the excited state (the fluorescence lifetime) reveals more detailed information about its local environment. The lifetime is measured in the time domain by detecting directly the decay of fluorescence following excitation by short pulse of light. The lifetime can also be measured in the frequency domain by recording the phase and amplitude of oscillation in the emitted fluorescence of the sample in response to repetitively modulated excitation light. In either the time or frequency domain, the analysis of data to extract lifetimes can be computationally intensive. For example, a variety of iterative fitting algorithms already exist to determine lifetimes from samples that contain multiple fluorescing species. However, recently a method of analysis referred to as the polar plot (or phasor plot) is a graphical tool that projects the time-dependent features of the sample's fluorescence in either the time or frequency domain into the Cartesian plane to characterize the sample's lifetime. The coordinate transformations of the polar plot require only the raw data, and hence, there are no uncertainties from extensive corrections or time-consuming fitting in this analysis. In this chapter, the history and mathematical background of the polar plot will be presented along with examples that highlight how it can be used in both cuvette-based and imaging applications.

Greens Function-Based Defect Identification in InAs-InA1-xSbx Strained Layer Superlattices (Postprint)

DTIC Science & Technology

2017-06-15

the GaSb valance band edge, in agreement with values deduced recently from lifetime measurements and analysis [Aytac et al . Phys. Rev. Appl., 5...meV below the GaSb valance band edge, in agreement with values deduced recently from lifetime mea- surements and analysis [Aytac et al . Phys. Rev

Designing for Maintainability and System Availability

NASA Technical Reports Server (NTRS)

Lalli, Vincent R.; Packard, Michael H.

1997-01-01

The final goal for a delivered system (whether a car, aircraft, avionics box or computer) should be its availability to operate and perform its intended function over its expected design life. Hence, in designing a system, we cannot think in terms of delivering the system and just walking away. The system supplier needs to provide support throughout the operating life of the product. Here, supportability requires an effective combination of reliability, maintainability, logistics and operations engineering (as well as safety engineering) to have a system that is available for its intended use throughout its designated mission lifetime. Maintainability is a key driving element in the effective support and upkeep of the system as well as providing the ability to modify and upgrade the system throughout its lifetime. This paper then, will concentrate on maintainability and its integration into the system engineering and design process. The topics to be covered include elements of maintainability, the total cost of ownership, how system availability, maintenance and logistics costs and spare parts cost effect the overall program costs. System analysis and maintainability will show how maintainability fits into the overall systems approach to project development. Maintainability processes and documents will focus on how maintainability is to be performed and what documents are typically generated for a large scale program. Maintainability analysis shows how trade-offs can be performed for various alternative components. The conclusions summarize the paper and are followed by specific problems for hands-on training.

The Association of Early Substance Use with Lifetime/Past Year Contraction of Sexually Transmitted Diseases: A National Study

ERIC Educational Resources Information Center

Merianos, Ashley L.; Rosen, Brittany L.; King, Keith A.; Vidourek, Rebecca A.; Fehr, Sara K.

2015-01-01

The study purpose is to examine the impact of early substance use on lifetime and past year contraction of sexually transmitted diseases (STDs), including chlamydia, gonorrhea, herpes, and syphilis. A secondary analysis of the 2012 National Survey on Drug Use and Health (N = 52,529) was conducted to determine if lifetime or past year STD…

Latent profile analysis and comorbidity in a sample of individuals with compulsive buying disorder.

PubMed

Mueller, Astrid; Mitchell, James E; Black, Donald W; Crosby, Ross D; Berg, Kelly; de Zwaan, Martina

2010-07-30

The aims of this study were to perform a latent profile analysis in a sample of individuals with compulsive buying, to explore the psychiatric comorbidity, and to examine whether or not more severe compulsive buying is associated with greater comorbidity. Compulsive buying measures and SCID data obtained from 171 patients with compulsive buying behavior who had participated in treatment trials at different clinical centers in the U.S. and Germany were analyzed. Latent profile analysis produced two clusters. Overall, cluster 2, included subjects with more severe compulsive buying, and was characterized by higher lifetime as well as current prevalence rates for Axis I and impulse control disorders. Nearly 90% of the total sample reported at least one lifetime Axis I diagnosis, particularly mood (74%) and anxiety (57%) disorders. Twenty-one percent had a comorbid impulse control disorder, most commonly intermittent explosive disorder (11%). Half of the sample presented with at least one current Axis I disorder, most commonly anxiety disorders (44%). Given the substantial psychiatric comorbidity, it is reasonable to question whether or not compulsive buying represents a distinct psychiatric entity vs. an epiphenomenon of other psychiatric disorders. Copyright 2010 Elsevier Ltd. All rights reserved.

Time resolved fluorescence of cow and goat milk powder

NASA Astrophysics Data System (ADS)

Brandao, Mariana P.; de Carvalho dos Anjos, Virgílio; Bell., Maria José V.

2017-01-01

Milk powder is an international dairy commodity. Goat and cow milk powders are significant sources of nutrients and the investigation of the authenticity and classification of milk powder is particularly important. The use of time-resolved fluorescence techniques to distinguish chemical composition and structure modifications could assist develop a portable and non-destructive methodology to perform milk powder classification and determine composition. This study goal is to differentiate milk powder samples from cows and goats using fluorescence lifetimes. The samples were excited at 315 nm and the fluorescence intensity decay registered at 468 nm. We observed fluorescence lifetimes of 1.5 ± 0.3, 6.4 ± 0.4 and 18.7 ± 2.5 ns for goat milk powder; and 1.7 ± 0.3, 6.9 ± 0.2 and 29.9 ± 1.6 ns for cow's milk powder. We discriminate goat and cow powder milk by analysis of variance using Fisher's method. In addition, we employed quadratic discriminant analysis to differentiate the milk samples with accuracy of 100%. Our results suggest that time-resolved fluorescence can provide a new method to the analysis of powder milk and its composition.

Phonon Lifetime Observation in Epitaxial ScN Film with Inelastic X-Ray Scattering Spectroscopy.

PubMed

Uchiyama, H; Oshima, Y; Patterson, R; Iwamoto, S; Shiomi, J; Shimamura, K

2018-06-08

Phonon-phonon scattering dominates the thermal properties in nonmetallic materials, and it directly influences device performance in applications. The understanding of the scattering has been progressing using computational approaches, and the direct and systematic observation of phonon modes that include momentum dependences is desirable. We report experimental data on the phonon dispersion curves and lifetimes in an epitaxially grown ScN film using inelastic x-ray scattering measurements. The momentum dependence of the optical phonon lifetimes is estimated from the spectral width, and the highest-energy phonon mode around the zone center is found to possess a short lifetime of 0.21 ps. A comparison with first-principles calculations shows that our observed phonon lifetimes are quantitatively explained by three-body phonon-phonon interactions.

Clinical results of fluorescence lifetime imaging in ophthalmology

NASA Astrophysics Data System (ADS)

Schweitzer, D.; Quick, S.; Klemm, M.; Hammer, M.; Jentsch, S.; Dawczynski, J.; Becker, W.

2009-07-01

A laser scanner ophthalmoscope was developed for in vivo fluorescence lifetime measurements at the human retina. Measurements were performed in 30 degree fundus images. The fundus was excited by pulses of 75 ps (FWHM). The dynamic fluorescence was detected in two spectral channels K1(490-560nm), K2(560-700 nm) by time-correlated single photon counting. The decay of fluorescence was three-exponentially. Local and global alterations in lifetimes were found between healthy subjects and patients suffering from age-related macular degeneration, diabetic retinopathy, and vessel occlusion. The lifetimes T1, T2, and T3 in both channels are changed to longer values in AMD and diabetic retinopathy in comparison with healthy subjects. The lifetime T2 in K1 is most sensitive to metabolic alterations in branch arterial vessel occlusion.

Phonon Lifetime Observation in Epitaxial ScN Film with Inelastic X-Ray Scattering Spectroscopy

NASA Astrophysics Data System (ADS)

Uchiyama, H.; Oshima, Y.; Patterson, R.; Iwamoto, S.; Shiomi, J.; Shimamura, K.

2018-06-01

Phonon-phonon scattering dominates the thermal properties in nonmetallic materials, and it directly influences device performance in applications. The understanding of the scattering has been progressing using computational approaches, and the direct and systematic observation of phonon modes that include momentum dependences is desirable. We report experimental data on the phonon dispersion curves and lifetimes in an epitaxially grown ScN film using inelastic x-ray scattering measurements. The momentum dependence of the optical phonon lifetimes is estimated from the spectral width, and the highest-energy phonon mode around the zone center is found to possess a short lifetime of 0.21 ps. A comparison with first-principles calculations shows that our observed phonon lifetimes are quantitatively explained by three-body phonon-phonon interactions.

Synthesis of ITO Powder by Dry Process and Lifetime Characteristics of the ITO Target Fabricated with its Powder

NASA Astrophysics Data System (ADS)

Takahashi, Seiichiro; Itoh, Hironori; Komatsu, Ryuichi

Lifetime of an indium tin oxide (ITO) target is an important characteristic in the production of liquid crystal displays (LCDs). Increasing the sintering density of the ITO target is assumed to lead to an increased lifetime. So far, it has been clarified that the carbon concentration in In2O3 powder, the raw material of ITO targets, influences remarkably the target lifetime. In this study, with the aim of reducing the concentration of carbon in In2O3 powder, the synthesis of In2O3 powder containing dissolved Sn by a dry process was performed.

Experimental radiative lifetimes, branching fractions, and oscillator strengths of some levels in Co I

NASA Astrophysics Data System (ADS)

Wang, Xinghao; Yu, Qi; Li, Qiu; Gao, Yang; Dai, Zhenwen

2018-04-01

The radiative lifetime measurements by the time-resolved laser-induced fluorescence technique are reported for 24 levels of Co I with the energy range of 283 45.86-55 922.3 cm-1, amongst which the lifetimes of 20 levels are reported for the first time. The branching fraction measurements by the emission spectrum of a hollow cathode lamp were performed for 11 levels of them together with other two levels reported in the literature, and branching fractions of 39 transitions were obtained. By combining them with lifetime values, the transition probabilities and absolute oscillator strengths of these lines were determined.

Excitation transfer and trapping kinetics in plant photosystem I probed by two-dimensional electronic spectroscopy.

PubMed

Akhtar, Parveen; Zhang, Cheng; Liu, Zhengtang; Tan, Howe-Siang; Lambrev, Petar H

2018-03-01

Photosystem I is a robust and highly efficient biological solar engine. Its capacity to utilize virtually every absorbed photon's energy in a photochemical reaction generates great interest in the kinetics and mechanisms of excitation energy transfer and charge separation. In this work, we have employed room-temperature coherent two-dimensional electronic spectroscopy and time-resolved fluorescence spectroscopy to follow exciton equilibration and excitation trapping in intact Photosystem I complexes as well as core complexes isolated from Pisum sativum. We performed two-dimensional electronic spectroscopy measurements with low excitation pulse energies to record excited-state kinetics free from singlet-singlet annihilation. Global lifetime analysis resolved energy transfer and trapping lifetimes closely matches the time-correlated single-photon counting data. Exciton energy equilibration in the core antenna occurred on a timescale of 0.5 ps. We further observed spectral equilibration component in the core complex with a 3-4 ps lifetime between the bulk Chl states and a state absorbing at 700 nm. Trapping in the core complex occurred with a 20 ps lifetime, which in the supercomplex split into two lifetimes, 16 ps and 67-75 ps. The experimental data could be modelled with two alternative models resulting in equally good fits-a transfer-to-trap-limited model and a trap-limited model. However, the former model is only possible if the 3-4 ps component is ascribed to equilibration with a "red" core antenna pool absorbing at 700 nm. Conversely, if these low-energy states are identified with the P 700 reaction centre, the transfer-to-trap-model is ruled out in favour of a trap-limited model.

Contributors to suicidality in rural communities: beyond the effects of depression

PubMed Central

2012-01-01

Background Rural populations experience a higher suicide rate than urban areas despite their comparable prevalence of depression. This suggests the identification of additional contributors is necessary to improve our understanding of suicide risk in rural regions. Investigating the independent contribution of depression, and the impact of co-existing psychiatric disorders, to suicidal ideation and suicide attempts in a rural community sample may provide clarification of the role of depression in rural suicidality. Methods 618 participants in the Australian Rural Mental Health Study completed the Composite International Diagnostic Interview, providing assessment of lifetime suicidal ideation and attempts, affective disorders, anxiety disorders and substance-use disorders. Logistic regression analyses explored the independent contribution of depression and additional diagnoses to suicidality. A receiver operating characteristic (ROC) analysis was performed to illustrate the benefit of assessing secondary psychiatric diagnoses when determining suicide risk. Results Diagnostic criteria for lifetime depressive disorder were met by 28% (174) of the sample; 25% (154) had a history of suicidal ideation. Overall, 41% (63) of participants with lifetime suicidal ideation and 34% (16) of participants with a lifetime suicide attempt had no history of depression. When lifetime depression was controlled for, suicidal ideation was predicted by younger age, being currently unmarried, and lifetime anxiety or post-traumatic stress disorder. In addition to depression, suicide attempts were predicted by lifetime anxiety and drug use disorders, as well as younger age; being currently married and employed were significant protective factors. The presence of comorbid depression and PTSD significantly increased the odds of reporting a suicide attempt above either of these conditions independently. Conclusions While depression contributes significantly to suicidal ideation, and is a key risk factor for suicide attempts, other clinical and demographic factors played an important role in this rural sample. Consideration of the contribution of factors such as substance use and anxiety disorders to suicidal ideation and behaviours may improve our ability to identify individuals at risk of suicide. Acknowledging the contribution of these factors to rural suicide may also result in more effective approaches for the identification and treatment of at-risk individuals. PMID:22873772

Positron lifetime in vanadium oxide bronzes

NASA Astrophysics Data System (ADS)

Dryzek, J.; Dryzek, E.

2003-09-01

The positron lifetime (PL) and Doppler broadening (DB) of annihilation line measurements have been performed in vanadium oxide bronzes MxV2O5. The dependence of these annihilation characteristics on the kind and concentration of the metal M donor has been observed. In the PL spectrum only one lifetime component has been detected in all studied bronzes. The results indicate the positron localization in the structural tunnels present in the crystalline lattice of the vanadium oxide bronzes. (

Degradation modeling of mid-power white-light LEDs by using Wiener process.

PubMed

Huang, Jianlin; Golubović, Dušan S; Koh, Sau; Yang, Daoguo; Li, Xiupeng; Fan, Xuejun; Zhang, G Q

2015-07-27

The IES standard TM-21-11 provides a guideline for lifetime prediction of LED devices. As it uses average normalized lumen maintenance data and performs non-linear regression for lifetime modeling, it cannot capture dynamic and random variation of the degradation process of LED devices. In addition, this method cannot capture the failure distribution, although it is much more relevant in reliability analysis. Furthermore, the TM-21-11 only considers lumen maintenance for lifetime prediction. Color shift, as another important performance characteristic of LED devices, may also render significant degradation during service life, even though the lumen maintenance has not reached the critical threshold. In this study, a modified Wiener process has been employed for the modeling of the degradation of LED devices. By using this method, dynamic and random variations, as well as the non-linear degradation behavior of LED devices, can be easily accounted for. With a mild assumption, the parameter estimation accuracy has been improved by including more information into the likelihood function while neglecting the dependency between the random variables. As a consequence, the mean time to failure (MTTF) has been obtained and shows comparable result with IES TM-21-11 predictions, indicating the feasibility of the proposed method. Finally, the cumulative failure distribution was presented corresponding to different combinations of lumen maintenance and color shift. The results demonstrate that a joint failure distribution of LED devices could be modeled by simply considering their lumen maintenance and color shift as two independent variables.

Lifetime Prediction of IGBT in a STATCOM Using Modified-Graphical Rainflow Counting Algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gopi Reddy, Lakshmi Reddy; Tolbert, Leon M; Ozpineci, Burak

Rainflow algorithms are one of the best counting methods used in fatigue and failure analysis [17]. There have been many approaches to the rainflow algorithm, some proposing modifications. Graphical Rainflow Method (GRM) was proposed recently with a claim of faster execution times [10]. However, the steps of the graphical method of rainflow algorithm, when implemented, do not generate the same output as the four-point or ASTM standard algorithm. A modified graphical method is presented and discussed in this paper to overcome the shortcomings of graphical rainflow algorithm. A fast rainflow algorithm based on four-point algorithm but considering point comparison thanmore » range comparison is also presented. A comparison between the performances of the common rainflow algorithms [6-10], including the proposed methods, in terms of execution time, memory used, and efficiency, complexity, and load sequences is presented. Finally, the rainflow algorithm is applied to temperature data of an IGBT in assessing the lifetime of a STATCOM operating for power factor correction of the load. From 5-minute data load profiles available, the lifetime is estimated to be at 3.4 years.« less

Targeted Victimization and Suicidality Among Trans People: A Web-Based Survey

PubMed Central

Dhejne, Cecilia; Orre, Carolina; Mannheimer, Louise Nilunger; Deogan, Charlotte; Höijer, Jonas; Winzer, Regina; Thorson, Anna Ekéus

2018-01-01

Abstract Purpose: The aim of this study was to investigate the associations between a series of empirically known risk and protective factors and suicidality among trans people in Sweden. Methods: Participants were self-selected anonymously to a web-based survey conducted in 2014. Univariable and multivariable logistic regression analyses were performed to assess associations between contributing factors and suicide ideation in the past 12 months and lifetime suicide attempts. Results: The analysis included 796 trans individuals, between 15 and 94 years of age, who live in Sweden. A total of 37% of respondents reported that they have seriously considered suicide during the past 12 months and 32% had ever attempted a suicide. Offensive treatment during the past three months and lifetime exposure to trans-related violence were significantly associated with suicidality. Less satisfaction with contacts with friends and acquaintances and with one's own psychological wellbeing were associated with suicide ideation in the past 12 months. Lack of practical support was associated with lifetime suicide attempts. Conclusions: Our findings show that suicidality is directly correlated with trans-related victimization. Preventing targeted victimization is, therefore, a key preventive intervention against this elevated suicidality. PMID:29641313

Randoms Counter Analysis

NASA Astrophysics Data System (ADS)

Hensley, Winston; Giovanetti, Kevin

2008-10-01

A 1 ppm precision measurement of the muon lifetime is being conducted by the MULAN collaboration. The reason for this new measurement lies in recent advances in theory that have reduced the uncertainty in calculating the Fermi Coupling Constant from the measured lifetime to a few tenths ppm. The largest uncertainty is now experimental. To achieve a 1ppm level of precision it is necessary to control all sources of systematic error and to understand their influences on the lifetime measurement. James Madison University is contributing by examine the response of the timing system to uncorrelated events, randoms. A radioactive source was placed in front of paired detectors similar to those in the main experiment. These detectors were integrated in an identical fashion into the data acquisition and measurement system and data from these detectors was recorded during the entire experiment. The pair were placed in a shielded enclosure away from the main experiment to minimize interference. The data from these detectors should have a flat time spectrum as the decay of a radioactive source is a random event and has no time correlation. Thus the spectrum can be used as an important diagnostic in studying the method of determining event times and timing system performance.

Full long-term design response analysis of a wave energy converter

DOE PAGES

Coe, Ryan G.; Michelen, Carlos; Eckert-Gallup, Aubrey; ...

2017-09-21

Efficient design of wave energy converters requires an accurate understanding of expected loads and responses during the deployment lifetime of a device. A study has been conducted to better understand best-practices for prediction of design responses in a wave energy converter. A case-study was performed in which a simplified wave energy converter was analyzed to predict several important device design responses. The application and performance of a full long-term analysis, in which numerical simulations were used to predict the device response for a large number of distinct sea states, was studied. Environmental characterization and selection of sea states for thismore » analysis at the intended deployment site were performed using principle-components analysis. The full long-term analysis applied here was shown to be stable when implemented with a relatively low number of sea states and convergent with an increasing number of sea states. As the number of sea states utilized in the analysis was increased, predicted response levels did not change appreciably. Furthermore, uncertainty in the response levels was reduced as more sea states were utilized.« less

Full long-term design response analysis of a wave energy converter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coe, Ryan G.; Michelen, Carlos; Eckert-Gallup, Aubrey

Efficient design of wave energy converters requires an accurate understanding of expected loads and responses during the deployment lifetime of a device. A study has been conducted to better understand best-practices for prediction of design responses in a wave energy converter. A case-study was performed in which a simplified wave energy converter was analyzed to predict several important device design responses. The application and performance of a full long-term analysis, in which numerical simulations were used to predict the device response for a large number of distinct sea states, was studied. Environmental characterization and selection of sea states for thismore » analysis at the intended deployment site were performed using principle-components analysis. The full long-term analysis applied here was shown to be stable when implemented with a relatively low number of sea states and convergent with an increasing number of sea states. As the number of sea states utilized in the analysis was increased, predicted response levels did not change appreciably. Furthermore, uncertainty in the response levels was reduced as more sea states were utilized.« less

Visible properties of Sm{sup 3+} ions in chloro-fluoro-borate glasses for reddish - orange emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, K. Venkata, E-mail: drvenkataraok@gmail.com; Babu, S.; Ratnakaram, Y. C.

2016-05-23

Optical properties of different concentration (0.2, 0.4, 0.6, 0.8 and 1.0 mol %) of Sm{sup 3+} doped chloro-fluoro-borate glasses have been synthesized and discussed. Structural characterizations have been studied through XRD analysis. Spectroscopic analysis has done from absorption spectra, luminescence spectra and decay lifetime profiles. From the emission spectra, concentration quenching is observed, with increase of samarium concentration and discussed behind the phenomena. The nature of decay curve analysis was performed for the {sup 4}G{sub 5/2} level. These glasses are expected to give interesting application in the field of optics.

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic radioactive waste repository: 2. Application to a Canadian Shield environment

NASA Astrophysics Data System (ADS)

Park, Y.-J.; Cornaton, F. J.; Normani, S. D.; Sykes, J. F.; Sudicky, E. A.

2008-04-01

F. J. Cornaton et al. (2008) introduced the concept of lifetime expectancy as a performance measure of the safety of subsurface repositories, on the basis of the travel time for contaminants released at a certain point in the subsurface to reach the biosphere or compliance area. The methodologies are applied to a hypothetical but realistic Canadian Shield crystalline rock environment, which is considered to be one of the most geologically stable areas on Earth. In an approximately 10 × 10 × 1.5 km3 hypothetical study area, up to 1000 major and intermediate fracture zones are generated from surface lineament analyses and subsurface surveys. In the study area, mean and probability density of lifetime expectancy are analyzed with realistic geologic and hydrologic shield settings in order to demonstrate the applicability of the theory and the numerical model for optimally locating a deep subsurface repository for the safe storage of spent nuclear fuel. The results demonstrate that, in general, groundwater lifetime expectancy increases with depth and it is greatest inside major matrix blocks. Various sources and aspects of uncertainty are considered, specifically geometric and hydraulic parameters of permeable fracture zones. Sensitivity analyses indicate that the existence and location of permeable fracture zones and the relationship between fracture zone permeability and depth from ground surface are the most significant factors for lifetime expectancy distribution in such a crystalline rock environment. As a consequence, it is successfully demonstrated that the concept of lifetime expectancy can be applied to siting and performance assessment studies for deep geologic repositories in crystalline fractured rock settings.

Reducing the Carbon Footprint of Commercial Refrigeration Systems Using Life Cycle Climate Performance Analysis: From System Design to Refrigerant Options

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, Brian A; Abdelaziz, Omar; Vineyard, Edward Allan

In this paper, Life Cycle Climate Performance (LCCP) analysis is used to estimate lifetime direct and indirect carbon dioxide equivalent gas emissions of various refrigerant options and commercial refrigeration system designs, including the multiplex DX system with various hydrofluorocarbon (HFC) refrigerants, the HFC/R744 cascade system incorporating a medium-temperature R744 secondary loop, and the transcritical R744 booster system. The results of the LCCP analysis are presented, including the direct and indirect carbon dioxide equivalent emissions for each refrigeration system and refrigerant option. Based on the results of the LCCP analysis, recommendations are given for the selection of low GWP replacement refrigerantsmore » for use in existing commercial refrigeration systems, as well as for the selection of commercial refrigeration system designs with low carbon dioxide equivalent emissions, suitable for new installations.« less

Concomitant medication of psychoses in a lifetime perspective.

PubMed

Vares, Maria; Saetre, Peter; Strålin, Pontus; Levander, Sten; Lindström, Eva; Jönsson, Erik G

2011-01-01

Patients treated with antipsychotic drugs often receive concomitant psychotropic compounds. Few studies address this issue from a lifetime perspective. Here, an analysis is presented of the prescription pattern of such concomitant medication from the first contact with psychiatry until the last written note in the case history documents, in patients with a diagnosis of psychotic illness. A retrospective descriptive analysis of all case history data of 66 patients diagnosed with schizophrenia or schizophrenia-like psychotic disorders. Benzodiazepines and benzodiazepine-related anxiolytic drugs had been prescribed to 95% of the patients, other anxiolytics, sedatives or hypnotic drugs to 61%, anti-parkinsonism drugs to 86%, and antidepressants to 56% of the patients. However, lifetime doses were small and most of the time patients had no concomitant medication. The prescribed lifetime dose of anti-parkinsonism drugs was associated with that of prescribed first-generation but not second-generation antipsychotics. Most psychosis patients are sometimes treated with concomitant drugs but mainly over short periods. Lifetime concomitant add-on medication at the individual patient level is variable and complex but not extensive. Copyright © 2011 John Wiley & Sons, Ltd.

The Correlation Between Dislocations and Vacancy Defects Using Positron Annihilation Spectroscopy

NASA Astrophysics Data System (ADS)

Pang, Jinbiao; Li, Hui; Zhou, Kai; Wang, Zhu

2012-07-01

An analysis program for positron annihilation lifetime spectra is only applicable to isolated defects, but is of no use in the presence of defective correlations. Such limitations have long caused problems for positron researchers in their studies of complicated defective systems. In order to solve this problem, we aim to take a semiconductor material, for example, to achieve a credible average lifetime of single crystal silicon under plastic deformation at different temperatures using positron life time spectroscopy. By establishing reasonable positron trapping models with defective correlations and sorting out four lifetime components with multiple parameters, as well as their respective intensities, information is obtained on the positron trapping centers, such as the positron trapping rates of defects, the density of the dislocation lines and correlation between the dislocation lines, and the vacancy defects, by fitting with the average lifetime with the aid of Matlab software. These results give strong grounds for the existence of dislocation-vacancy correlation in plastically deformed silicon, and lay a theoretical foundation for the analysis of positron lifetime spectra when the positron trapping model involves dislocation-related defects.

Validity of LIDAS (LIfetime Depression Assessment Self-report): a self-report online assessment of lifetime major depressive disorder.

PubMed

Bot, M; Middeldorp, C M; de Geus, E J C; Lau, H M; Sinke, M; van Nieuwenhuizen, B; Smit, J H; Boomsma, D I; Penninx, B W J H

2017-01-01

There is a paucity of valid, brief instruments for the assessment of lifetime major depressive disorder (MDD) that can be used in, for example, large-scale genomics, imaging or biomarker studies on depression. We developed the LIfetime Depression Assessment Self-report (LIDAS), which assesses lifetime MDD diagnosis according to DSM criteria, and is largely based on the widely used Composite International Diagnostic Interview (CIDI). Here, we tested the feasibility and determined the sensitivity and specificity for measuring lifetime MDD with this new questionnaire, with a regular CIDI as reference. Sensitivity and specificity analyses of the online lifetime MDD questionnaire were performed in adults with (n = 177) and without (n = 87) lifetime MDD according to regular index CIDIs, selected from the Netherlands Study of Depression and Anxiety (NESDA) and Netherlands Twin Register (NTR). Feasibility was tested in an additional non-selective, population-based sample of NTR participants (n = 245). Of the 753 invited persons, 509 (68%) completed the LIDAS, of which 419 (82%) did this online. User-friendliness of the instrument was rated high. Median completion time was 6.2 min. Sensitivity and specificity for lifetime MDD were 85% [95% confidence interval (CI) 80-91%] and 80% (95% CI 72-89%), respectively. This LIDAS instrument gave a lifetime MDD prevalence of 20.8% in the population-based sample. Measuring lifetime MDD with an online instrument was feasible. Sensitivity and specificity were adequate. The instrument gave a prevalence of lifetime MDD in line with reported population prevalences. LIDAS is a promising tool for rapid determination of lifetime MDD status in large samples, such as needed for genomics studies.

Rapid Global Fitting of Large Fluorescence Lifetime Imaging Microscopy Datasets

PubMed Central

Warren, Sean C.; Margineanu, Anca; Alibhai, Dominic; Kelly, Douglas J.; Talbot, Clifford; Alexandrov, Yuriy; Munro, Ian; Katan, Matilda

2013-01-01

Fluorescence lifetime imaging (FLIM) is widely applied to obtain quantitative information from fluorescence signals, particularly using Förster Resonant Energy Transfer (FRET) measurements to map, for example, protein-protein interactions. Extracting FRET efficiencies or population fractions typically entails fitting data to complex fluorescence decay models but such experiments are frequently photon constrained, particularly for live cell or in vivo imaging, and this leads to unacceptable errors when analysing data on a pixel-wise basis. Lifetimes and population fractions may, however, be more robustly extracted using global analysis to simultaneously fit the fluorescence decay data of all pixels in an image or dataset to a multi-exponential model under the assumption that the lifetime components are invariant across the image (dataset). This approach is often considered to be prohibitively slow and/or computationally expensive but we present here a computationally efficient global analysis algorithm for the analysis of time-correlated single photon counting (TCSPC) or time-gated FLIM data based on variable projection. It makes efficient use of both computer processor and memory resources, requiring less than a minute to analyse time series and multiwell plate datasets with hundreds of FLIM images on standard personal computers. This lifetime analysis takes account of repetitive excitation, including fluorescence photons excited by earlier pulses contributing to the fit, and is able to accommodate time-varying backgrounds and instrument response functions. We demonstrate that this global approach allows us to readily fit time-resolved fluorescence data to complex models including a four-exponential model of a FRET system, for which the FRET efficiencies of the two species of a bi-exponential donor are linked, and polarisation-resolved lifetime data, where a fluorescence intensity and bi-exponential anisotropy decay model is applied to the analysis of live cell homo-FRET data. A software package implementing this algorithm, FLIMfit, is available under an open source licence through the Open Microscopy Environment. PMID:23940626

Dynamics of history-dependent epidemics in temporal networks

NASA Astrophysics Data System (ADS)

Sunny, Albert; Kotnis, Bhushan; Kuri, Joy

2015-08-01

The structural properties of temporal networks often influence the dynamical processes that occur on these networks, e.g., bursty interaction patterns have been shown to slow down epidemics. In this paper, we investigate the effect of link lifetimes on the spread of history-dependent epidemics. We formulate an analytically tractable activity-driven temporal network model that explicitly incorporates link lifetimes. For Markovian link lifetimes, we use mean-field analysis for computing the epidemic threshold, while the effect of non-Markovian link lifetimes is studied using simulations. Furthermore, we also study the effect of negative correlation between the number of links spawned by an individual and the lifetimes of those links. Such negative correlations may arise due to the finite cognitive capacity of the individuals. Our investigations reveal that heavy-tailed link lifetimes slow down the epidemic, while negative correlations can reduce epidemic prevalence. We believe that our results help shed light on the role of link lifetimes in modulating diffusion processes on temporal networks.

EqualChance: Addressing Intra-set Write Variation to Increase Lifetime of Non-volatile Caches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mittal, Sparsh; Vetter, Jeffrey S

To address the limitations of SRAM such as high-leakage and low-density, researchers have explored use of non-volatile memory (NVM) devices, such as ReRAM (resistive RAM) and STT-RAM (spin transfer torque RAM) for designing on-chip caches. A crucial limitation of NVMs, however, is that their write endurance is low and the large intra-set write variation introduced by existing cache management policies may further exacerbate this problem, thereby reducing the cache lifetime significantly. We present EqualChance, a technique to increase cache lifetime by reducing intra-set write variation. EqualChance works by periodically changing the physical cache-block location of a write-intensive data item withinmore » a set to achieve wear-leveling. Simulations using workloads from SPEC CPU2006 suite and HPC (high-performance computing) field show that EqualChance improves the cache lifetime by 4.29X. Also, its implementation overhead is small, and it incurs very small performance and energy loss.« less

Carbon contamination topography analysis of EUV masks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Y.-J.; Yankulin, L.; Thomas, P.

2010-03-12

The impact of carbon contamination on extreme ultraviolet (EUV) masks is significant due to throughput loss and potential effects on imaging performance. Current carbon contamination research primarily focuses on the lifetime of the multilayer surfaces, determined by reflectivity loss and reduced throughput in EUV exposure tools. However, contamination on patterned EUV masks can cause additional effects on absorbing features and the printed images, as well as impacting the efficiency of cleaning process. In this work, several different techniques were used to determine possible contamination topography. Lithographic simulations were also performed and the results compared with the experimental data.

High lifetime and reproductive performance of sows on southern European Union commercial farms can be predicted by high numbers of pigs born alive in parity one.

PubMed

Iida, R; Piñeiro, C; Koketsu, Y

2015-05-01

Our objectives were 1) to compare reproductive performance across parity and lifetime performance in sow groups categorized by the number of pigs born alive (PBA) in parity 1 and 2) to examine the factors associated with more PBA in parity 1. We analyzed 476,816 parity records and 109,373 lifetime records of sows entered into 125 herds from 2008 to 2010. Sows were categorized into 4 groups based on the 10th, 50th, and 90th percentiles of PBA in parity 1 as follows: 7 pigs or fewer, 8 to 11 pigs, 12 to 14 pigs, and 15 pigs or more. Generalized linear models were applied to the data. For reproductive performance across parity, sows that had 15 or more PBA in parity 1 had 0.5 to 1.8 more PBA in any subsequent parity than the other 3 PBA groups ( P< 0.05). In addition, they had 2.8 to 5.4% higher farrowing rates in parities 1 through 3 than sows that had 7 or fewer PBA (P < 0.05). However, there were no differences between the sow PBA groups for weaning-to-first-mating interval in any parity (P ≥ 0.37). For lifetime performance, sows that had 15 or more PBA in parity 1 had 4.4 to 26.1 more lifetime PBA than sows that had 14 or fewer PBA (P < 0.05). Also, for sows that had 14 or fewer PBA in parity 1, those that were first mated at 229 d old (25th percentile) or earlier had 2.9 to 3.3 more lifetime PBA than those first mated at 278 d old (75th percentile) or later (P < 0.05). Factors associated with fewer PBA in parity 1 were summer mating and lower age of gilts at first mating (AFM; P < 0.05) but not reservice occurrences (P = 0.34). Additionally, there was a 2-way interaction between mated month groups and AFM for PBA in parity 1 (P < 0.05); PBA in parity 1 sows mated from July to December increased nonlinearly by 0.3 to 0.4 pigs when AFM increased from 200 to 310 d old (P < 0.05). However, the same rise in AFM had no significant effect on the PBA of sows mated between January and June (P ≥ 0.17). In conclusion, high PBA in parity 1 can be used to predict that a sow will have high reproductive performance and lifetime performance. Also, the data indicate that the upper limit of AFM for mating between July and December should be 278 d old.

Spectroscopic analysis of transition state energy levels - Bending-rotational spectrum and lifetime analysis of H3 quasibound states

NASA Technical Reports Server (NTRS)

Zhao, Meishan; Mladenovic, Mirjana; Truhlar, Donald G.; Schwenke, David W.; Sharafeddin, Omar

1989-01-01

Converged quantum mechanical calculations of scattering matrices and transition probabilities are reported for the reaction of H with H2 with total angular momentum 0, 1, and 4 as functions of total energy in the range 0.85-1.15 eV on an accurate potential energy surface. The resonance structure is illustrated with Argand diagrams. State-to-state reactive collision delay times and lifetimes are presented. For J = 0, 1, and 4, the lowest-energy H3 resonance is at total energies of 0.983, 0.985, and 1.01 eV, respectively, with lifetimes of about 16-17 fs. For J = 1 and 4 there is a higher-energy resonance at 1.10-1.11 eV. For J = 1 the lifetime is about 4 fs and for J = 4 it is about 1 fs.

In Situ, On-Demand Lubrication System Developed for Space Mechanisms

NASA Technical Reports Server (NTRS)

Marchetti, Mario; Pepper, Stephen V.; Jansen, Mark J.; Predmore, Roamer E.

2003-01-01

Many moving mechanical assemblies (MMA) for space mechanisms rely on liquid lubricants to provide reliable, long-term performance. The proper performance of the MMA is critical in assuring a successful mission. Historically, mission lifetimes were short and MMA duty cycles were minimal. As mission lifetimes were extended, other components, such as batteries and computers, failed before lubricated systems. However, improvements in these ancillary systems over the last decade have left the tribological systems of the MMAs as the limiting factor in determining spacecraft reliability. Typically, MMAs are initially lubricated with a very small charge that is supposed to last the entire mission lifetime, often well in excess of 5 years. In many cases, the premature failure of a lubricated component can result in mission failure.

Time resolved photo-luminescent decay characterization of mercury cadmium telluride focal plane arrays

DOE PAGES

Soehnel, Grant

2015-01-20

The minority carrier lifetime is a measurable material property that is an indication of infrared detector device performance. To study the utility of measuring the carrier lifetime, an experiment has been constructed that can time resolve the photo-luminescent decay of a detector or wafer sample housed inside a liquid nitrogen cooled Dewar. Motorized stages allow the measurement to be scanned over the sample surface, and spatial resolutions as low as 50µm have been demonstrated. A carrier recombination simulation was developed to analyze the experimental data. Results from measurements performed on 4 mercury cadmium telluride focal plane arrays show strong correlationmore » between spatial maps of the lifetime, dark current, and relative response.« less

Bariatric surgery for the treatment of severely obese patients in South Korea--is it cost effective?

PubMed

Song, Hyun Jin; Kwon, Jin Won; Kim, Yong Jin; Oh, Sung-Hee; Heo, Yoonseok; Han, Sang-Moon

2013-12-01

In South Korea, the number of severely obese patients has increased. An economic study comparing bariatric surgery with nonsurgical interventions has not been published for Asia. This study was conducted to evaluate the cost effectiveness of bariatric surgery as compared to nonsurgical interventions for severe obese Korean people. We used the Markov model to compare the lifetime expected costs and quality-adjusted life years (QALYs) between bariatric surgery and nonsurgical interventions from Korean Healthcare system perspectives. Our target cohort consisted of severe obese people defined as having a body mass index of 30-<40 kg/m(2) in South Korea. The starting age of the cohort was 30 years old, and the cycle length was 1 year. Nonsurgical interventions included a physician visit, exercise, diet, and pharmacotherapy. A discount of 5 % was applied in cost and QALY. The incremental cost-effectiveness ratio (ICER) of bariatric surgery compared to nonsurgery interventions was calculated. The cost-utility analysis study indicated that bariatric surgery had US$1,522 incremental costs and 0.86 incremental QALYs as compared to nonsurgical interventions. Through the base case analysis, ICER was US$1,771/QALY. The sensitivity analyses were performed using a variety of assumptions, and the robustness of the study results was also demonstrated. The study indicated that bariatric surgery was a cost-effective alternative to nonsurgical interventions over a lifetime, providing substantial lifetime benefits for severely obese Korean people.

Reduced memory and attention performance in a population-based sample of young adults with a moderate lifetime use of cannabis, ecstasy and alcohol.

PubMed

Indlekofer, F; Piechatzek, M; Daamen, M; Glasmacher, C; Lieb, R; Pfister, H; Tucha, O; Lange, K W; Wittchen, H U; Schütz, C G

2009-07-01

Regular use of illegal drugs is suspected to cause cognitive impairments. Two substances have received heightened attention: 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy') and delta-9-tetrahydrocannabinol (THC or 'cannabis'). Preclinical evidence, as well as human studies examining regular ecstasy consumers, indicated that ecstasy use may have negative effects on learning, verbal memory and complex attentional functions. Cannabis has also been linked to symptoms of inattention and deficits in learning and memory. Most of the published studies in this field of research recruited participants by means of newspaper advertisements or by using word-of-mouth strategies. Because participants were usually aware that their drug use was critical to the research design, this awareness may have caused selection bias or created expectation effects. Focussing on attention and memory, this study aimed to assess cognitive functioning in a community-based representative sample that was derived from a large-scale epidemiological study. Available data concerning drug use history allowed sampling of subjects with varying degrees of lifetime drug experiences. Cognitive functioning was examined in 284 young participants, between 22 and 34 years. In general, their lifetime drug experience was moderate. Participants completed a neuropsychological test battery, including measures for verbal learning, memory and various attentional functions. Linear regression analysis was performed to investigate the relationship between cognitive functioning and lifetime experience of drug use. Ecstasy and cannabis use were significantly related to poorer episodic memory function in a dose-related manner. For attentional measures, decrements of small effect sizes were found. Error measures in tonic and phasic alertness tasks, selective attention task and vigilance showed small but significant effects, suggesting a stronger tendency to experience lapses of attention. No indication for differences in reaction time was found. The results are consistent with decrements of memory and attentional performance described in previous studies. These effects are relatively small; however, it must be kept in mind that this study focussed on assessing young adults with moderate drug use from a population-based study.

Correlates of partner and family violence among older Canadians: a life-course approach.

PubMed

Miszkurka, M; Steensma, C; Phillips, S P

2016-03-01

Knowledge about individual and interpersonal correlates of violence in Canadian seniors is limited. This study identifies correlates of current and past violence by intimate partner and family member(s) in community-dwelling Canadian seniors, while accounting for childhood adverse circumstances. We performed logistic regression analysis of baseline data from a longitudinal study of community-dwelling individuals aged 65 to 74 years and living in Kingston (Ontario) and Saint-Hyacinthe (Quebec). Domestic violence was assessed using the Hurt- Insult-Threaten-Scream (HITS) screening tool. Odds ratios (ORs) are reported with 95% confidence intervals (CIs). Current violence of a psychological nature was reported by 18% of the sample. Women were at greater risk of current and lifetime violence perpetrated by a family member (current violence: adjusted OR = 1.83; 95% CI: 1.02-3.30) as well as experiencing violence from their intimate partner in their lifetime than were men (adjusted OR = 2.48; 95% CI: 1.40-4.37). Risk factors have accumulated over the life course that were found to be consistently associated with both current and lifetime violence included having witnessed violence at home in childhood (lifetime violence by family member: adjusted OR = 9.46; 95% CI: 5.11-17.52), as well as poor quality of relationships with intimate partners, family and friends. Our research documents the ongoing impact of early adversity on subsequent partner and family violence in Canada. Findings identify some preventable factors associated with current psychological violence and past violence among community dwelling Canadian seniors.

Alcohol consumption in movies and adolescent binge drinking in 6 European countries.

PubMed

Hanewinkel, Reiner; Sargent, James D; Poelen, Evelien A P; Scholte, Ron; Florek, Ewa; Sweeting, Helen; Hunt, Kate; Karlsdottir, Solveig; Jonsson, Stefan Hrafn; Mathis, Federica; Faggiano, Fabrizio; Morgenstern, Matthis

2012-04-01

The goal of this study was to investigate whether the association between exposure to images of alcohol use in movies and binge drinking among adolescents is independent of cultural context. A cross-sectional survey study in 6 European countries (Germany, Iceland, Italy, Netherlands, Poland, and Scotland) was conducted. A total of 16 551 pupils from 114 public schools with a mean (± SD) age of 13.4 (± 1.18) years participated. By using previously validated methods, exposure to alcohol use in movies was estimated from the 250 top-grossing movies of each country (years 2004-2009). Lifetime binge drinking was the main outcome measure. Overall, 27% of the sample had consumed >5 drinks on at least 1 occasion in their life. After controlling for age, gender, family affluence, school performance, television screen time, sensation seeking and rebelliousness, and frequency of drinking of peers, parents, and siblings, the adjusted β-coefficient for lifetime binge drinking in the entire sample was 0.12 (95% confidence interval: 0.10-0.14; P < .001). The crude relationship between movie alcohol use exposure and lifetime binge drinking was significant in all countries; after covariate adjustment, the relationship was still significant in 5 of 6 countries. A sensitivity analysis revealed that the association is content specific, as there was no significant association between lifetime binge drinking and exposure to smoking in movies. The link between alcohol use in movies and adolescent binge drinking was robust and seems relatively unaffected by cultural contexts.

Using bibliometrics to analyze the state of academic productivity in US pediatric surgery training programs.

PubMed

Desai, Nidhi; Veras, Laura V; Gosain, Ankush

2018-06-01

The Accreditation Council for Graduate Medical Education (ACGME) Common Program Requirements state that faculty must establish and maintain an environment of inquiry and scholarship. Bibliometrics, the statistical analysis of written publications, assesses scientific productivity and impact. The goal of this study was to understand the state of scholarship at Pediatric Surgery training programs. Following IRB approval, Scopus was used to generate bibliometric profiles for US Pediatric Surgery training programs and faculty. Statistical analyses were performed. Information was obtained for 430 surgeons (105 female) from 48 US training programs. The mean lifetime h-index/surgeon for programs was 14.4 +/- 4.7 (6 programs above 1 SD, 9 programs below 1 SD). The mean 5-yearh-index/surgeon for programs was 3.92 +/- 1.5 (7 programs above 1 SD, 8 programs below 1 SD). Programs accredited after 2000 had a lower lifetime h-index than those accredited before 2000 (p=0.0378). Female surgeons had a lower lifetime h-index (p<0.0001), 5-yearh-index (p=0.0049), and m-quotient (p<0.0001) compared to males. Mean lifetime h-index increased with academic rank (p<0.0001), with no gender differences beyond the assistant professor rank (p=NS). Variability was identified based on institution, gender, and rank. This information can be used for benchmarking the academic productivity of faculty and programs and as an adjunct in promotion/tenure decisions. Original Research. n/a. Copyright © 2018 Elsevier Inc. All rights reserved.

Coupled modeling of the competitive gettering of transition metals and impact on performance of lifetime sensitive devices

NASA Astrophysics Data System (ADS)

Yazdani, Armin; Chen, Renyu; Dunham, Scott T.

2017-03-01

This work models competitive gettering of metals (Cu, Ni, Fe, Mo, and W) by boron, phosphorus, and dislocation loops, and connects those results directly to device performance. Density functional theory calculations were first performed to determine the binding energies of metals to the gettering sites, and based on that, continuum models were developed to model the redistribution and trapping of the metals. Our models found that Fe is most strongly trapped by the dislocation loops while Cu and Ni are most strongly trapped by the P4V clusters formed in high phosphorus concentrations. In addition, it is found that none of the mentioned gettering sites are effective in gettering Mo and W. The calculated metal redistribution along with the associated capture cross sections and trap energy levels are passed to device simulation via the recombination models to calculate carrier lifetime and the resulting device performance. Thereby, a comprehensive and predictive TCAD framework is developed to optimize the processing conditions to maximize performance of lifetime sensitive devices.

Lifetime estimates for sterilizable silver-zinc battery separators

NASA Technical Reports Server (NTRS)

Cuddihy, E. F.; Walmsley, D. E.; Moacanin, J.

1972-01-01

The lifetime of separator membranes currently employed in the electrolyte environment of silver-zinc batteries was estimated at 3 to 5 years. The separator membranes are crosslinked polyethylene film containing grafted poly (potassium acrylate)(PKA), the latter being the hydrophilic agent which promotes electrolyte ion transport. The lifetime was estimated by monitoring the rate of loss of PKA from the separators, caused by chemical attack of the electrolyte, and relating this loss rate to a known relationship between battery performance and PKA concentration in the separators.

White-Light Supercontinuum Laser-Based Multiple Wavelength Excitation for TCSPC-FLIM of Cutaneous Nanocarrier Uptake

NASA Astrophysics Data System (ADS)

Volz, Pierre; Brodwolf, Robert; Zoschke, Christian; Haag, Rainer; Schäfer-Korting, Monika; Alexiev, Ulrike

2018-05-01

We report here on a custom-built time-correlated single photon-counting (TCSPC)-based fluorescence lifetime imaging microscopy (FLIM) setup with a continuously tunable white-light supercontinuum laser combined with acousto-optical tunable filters (AOTF) as an excitation source for simultaneous excitation of multiple spectrally separated fluorophores. We characterized the wavelength dependence of the white-light supercontinuum laser pulse properties and demonstrated the performance of the FLIM setup, aiming to show the experimental setup in depth together with a biomedical application. We herein summarize the physical-technical parameters as well as our approach to map the skin uptake of nanocarriers using FLIM with a resolution compared to spectroscopy. As an example, we focus on the penetration study of indocarbocyanine-labeled dendritic core-multishell nanocarriers (CMS-ICC) into reconstructed human epidermis. Unique fluorescence lifetime signatures of indocarbocyanine-labeled nanocarriers indicate nanocarrier-tissue interactions within reconstructed human epidermis, bringing FLIM close to spectroscopic analysis.

Imaging dental sections with polarization-resolved SHG and time-resolved autofluorescence

NASA Astrophysics Data System (ADS)

Chen, Jun Huang; Lin, Po-Yen; Hsu, Stephen C. Y.; Kao, Fu-Jen

2009-02-01

In this study, we are using two-photon (2-p) excited autofluorescence and second harmonic (SH) as imaging modalities to investigate dental sections that contains the enamel and the dentin. The use of near-infrared wavelengths for multiphoton excitation greatly facilitates the observation of these sections due to the hard tissue's larger index of refraction and highly scattering nature. Clear imaging can be achieved without feature altering preparation procedures of the samples. Specifically, we perform polarization resolving on SH and lifetime analysis on autofluorescence. Polarization resolved SH reflects the preferred orientation of collagen while very different autofluorescence lifetimes are observed from the dentin and the enamel. The origin of 2-p autofluorescence and SH signals are attributed to hydroxyapatite crystals and collagen fibrils, respectively. Hydroxyapatite is found to be present throughout the sections while collagen fibrils exist only in the dentin and dentinoenamel junctions.

Investigation of the local environment of Eu3+ in a silicophosphate glass using site-selective spectroscopy and Molecular Dynamics simulations

NASA Astrophysics Data System (ADS)

Ben Slimen, F.; Haouari, M.; Ben Ouada, H.; Guichaoua, D.; Raso, P.; Bidault, X.; Turlier, J.; Gaumer, N.; Chaussedent, S.

2017-02-01

Silicophosphate glasses (SiO2-P2O5) doped with Eu3+ ions were synthesized by the sol-gel process. Optical properties of these glasses were investigated by means of emission spectra and lifetime measurements. The Fluorescence Line Narrowing (FLN) technique was also used to explore the local structure around the Eu3+ ions in this host and to understand the role of phosphate as a codopant. As it is the case for aluminum, the ability of phosphate to avoid the rare earth clustering was investigated, and the role of this codopant in modifying the local order around the rare earth ion was evidenced. The analysis of the FLN spectra and lifetime measurements is consistent with this interpretation. Molecular Dynamics simulations were performed to evaluate and confirm these structural features. Two classes of europium sites were distinguished in agreement with the experimental characterization.

An Investigation of Catastrophic Failure in Solid-State Lamps Exposed to Harsh Environment Operational Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lall, Pradeep; Sakalaukus, Peter; Davis, Lynn

2015-07-06

Today’s lighting technology is steadily becoming more energy efficient and less toxic to the environment since the passing of the Energy Independence and Security Act of 2007 (EISA) [1]. EISA has mandated a higher energy efficiency standard for lighting products and the phase out of the common incandescent lamp. This has led lighting manufacturers to pursue solid-state lighting (SSL) technologies for consumer lighting applications. However, two major roadblocks are hindering the transition process to SSL lamps: cost and quality. In order to cut cost, manufactures are moving towards cheaper packaging materials and a variety of package architecture construction techniques whichmore » may potentially erode the quality of the lamp and reduce its survivability in everyday applications. Typically, SSL lamps are given product lifetimes of over twenty years based off of the IES TM-21-11 lighting standard which does not include moisture effects or large operational temperatures [2]. A group of recently released off-the-shelf lamps have undergone a steady-state temperature humidity bias life test of 85°C/85%RH (85/85) to investigate the reliability in harsh environment applications. The lack of accelerated test methods for lamps to assess reliability prior to introduction into the marketplace does not exist in literature. There is a need for SSL physics based models for the assessment and prediction of a lamp’s lifetime which is being spearheaded by the DOE [3]. In order to be fully accepted in the marketplace, SSL lamps must be able to perform similarly to incandescent lamps in these environments, as well as live up to the lifetime claims of manufacturers. A lamp’s package architecture must be designed with performance factors in mind, as well as address some of the known and published package related failure mechanisms, such as carbonization of the encapsulant material, delamination, encapsulant yellowing, lens cracking, and phosphor thermal quenching [4]. Each failure mechanism produces the similar failure mode of lumen degradation predominately due to two contributing factors: high junction temperature and moisture ingress. The current state-of-the-art has focused on individual areas of the lamp, such as the LED chip, substrate material, electrical driver design and thermal management techniques. [5] – [16] Looking at the lamp as a whole is a novel approach and has not been seen before in literature. This work followed the JEDEC standard JESD22-A101C of 85/85 with a one hour interval of applied voltage followed by a one hour interval of no applied voltage [17]. This test was performed continuously for each SSL lamp until it became nonoperational, i.e. did not turn on. Periodically, photometric measurements were taken following the IES LM-79-08 standard at room temperature using an integrating sphere, a spectrometer, and lighting software. The overall health of the SSL lamps was assed using the relative luminous flux (RLF), correlated color temperature (CCT) and the color difference (Δu'v') using the Euclidean distance of the CIE 1976 color space coordinates. Finally, a Weibull analysis was completed to compare the characteristic lifetime of the SSL lamp to the actual rated lifetime. An important result from this work shows that the rated lifetime does not come close to the actual lifetime when the SSL lamps are used in a harsh humid environment which is fairly common in outdoor applications across the U.S. Also, the photometric results are presented for the entire lifetime of each SSL lamp under test.« less

A Lifetime Prevalence of Comorbidity Between Bipolar Affective Disorder and Anxiety Disorders: A Meta-analysis of 52 Interview-based Studies of Psychiatric Population

PubMed Central

Nabavi, Behrouz; Mitchell, Alex J.; Nutt, David

2015-01-01

Background Bipolar affective disorder has a high rate of comorbidity with a multitude of psychiatric disorders and medical conditions. Among all the potential comorbidities, co-existing anxiety disorders stand out due to their high prevalence. Aims To determine the lifetime prevalence of comorbid anxiety disorders in bipolar affective disorder under the care of psychiatric services through systematic review and meta-analysis. Method Random effects meta-analyses were used to calculate the lifetime prevalence of comorbid generalised anxiety disorder, panic disorder, social anxiety disorder, specific phobia, agoraphobia, obsessive compulsive disorder and posttraumatic stress disorder in bipolar affective disorder. Results 52 studies were included in the meta-analysis. The rate of lifetime comorbidity was as follows: panic disorder 16.8% (95% CI 13.7–20.1), generalised anxiety disorder 14.4% (95% CI 10.8–18.3), social anxiety disorder13.3% (95% CI 10.1–16.9), post-traumatic stress disorder 10.8% (95% CI 7.3–14.9), specific phobia 10.8% (95% CI 8.2–13.7), obsessive compulsive disorder 10.7% (95% CI 8.7–13.0) and agoraphobia 7.8% (95% CI 5.2–11.0). The lifetime prevalence of any anxiety disorders in bipolar disorder was 42.7%. Conclusions Our results suggest a high rate of lifetime concurrent anxiety disorders in bipolar disorder. The diagnostic issues at the interface are particularly difficult because of the substantial symptom overlap. The treatment of co-existing conditions has clinically remained challenging. PMID:26629535

An air-breathing enzymatic cathode with extended lifetime by continuous laccase supply.

PubMed

Kipf, Elena; Sané, Sabine; Morse, Daniel; Messinger, Thorsten; Zengerle, Roland; Kerzenmacher, Sven

2018-04-22

We present a novel concept of an air-breathing enzymatic biofuel cell cathode combined with continuous supply of unpurified laccase-containing supernatant of the white-rot fungus Trametes versicolor for extended lifetime. The air-breathing cathode design obviates the need for energy-intensive active aeration. In a corresponding long-term experiment at a constant current density of 50 µA cm -2 , we demonstrated an increased lifetime of 33 days (cathode potential above 0.430 V vs. SCE), independent of enzyme degradation. The obtained data suggest that theoretically a longer lifetime is feasible. However, further engineering efforts are required to prevent clogging and fouling of the supply tubes. These results represent an important step towards the realization of enzymatic biofuel cell cathodes with extended lifetime and enhanced performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Do thermal donors reduce the lifetimes of Czochralski-grown silicon crystals?

NASA Astrophysics Data System (ADS)

Miyamura, Y.; Harada, H.; Nakano, S.; Nishizawa, S.; Kakimoto, K.

2018-05-01

High-performance electronics require long carrier lifetimes within their silicon crystals. This paper reports the effects of thermal donors on the lifetimes of carriers in as-grown n-type silicon crystals grown by the Czochralski method. We grew silicon crystals with two different concentrations of thermal donors using the following two cooling processes: one was cooled with a 4-h halt after detaching the crystal from the melt, and the other was cooled continuously. The crystal grown with the cooling halt contained higher concentrations of thermal donors of the order of 1 × 1013 cm-3, while the crystal without the halt had no thermal donors. The measured bulk lifetimes were in the range of 15-18 ms. We concluded that thermal donors in Czochralski-grown silicon crystals do not act to reduce their lifetimes.

Statistical evidence of strain induced breaking of metallic point contacts

NASA Astrophysics Data System (ADS)

Alwan, Monzer; Candoni, Nadine; Dumas, Philippe; Klein, Hubert R.

2013-06-01

A scanning tunneling microscopy in break junction regime and a mechanically controllable break junction are used to acquire thousands of conductance-elongation curves by stretching until breaking and re-connecting Au junctions. From a robust statistical analysis performed on large sets of experiments, parameters such as lifetime, elongation and occurrence probabilities are extracted. The analysis of results obtained for different stretching speeds of the electrodes indicates that the breaking mechanism of di- and mono-atomic junction is identical, and that the junctions undergo atomic rearrangement during their stretching and at the moment of breaking.

3D-resolved fluorescence and phosphorescence lifetime imaging using temporal focusing wide-field two-photon excitation

PubMed Central

Choi, Heejin; Tzeranis, Dimitrios S.; Cha, Jae Won; Clémenceau, Philippe; de Jong, Sander J. G.; van Geest, Lambertus K.; Moon, Joong Ho; Yannas, Ioannis V.; So, Peter T. C.

2012-01-01

Fluorescence and phosphorescence lifetime imaging are powerful techniques for studying intracellular protein interactions and for diagnosing tissue pathophysiology. While lifetime-resolved microscopy has long been in the repertoire of the biophotonics community, current implementations fall short in terms of simultaneously providing 3D resolution, high throughput, and good tissue penetration. This report describes a new highly efficient lifetime-resolved imaging method that combines temporal focusing wide-field multiphoton excitation and simultaneous acquisition of lifetime information in frequency domain using a nanosecond gated imager from a 3D-resolved plane. This approach is scalable allowing fast volumetric imaging limited only by the available laser peak power. The accuracy and performance of the proposed method is demonstrated in several imaging studies important for understanding peripheral nerve regeneration processes. Most importantly, the parallelism of this approach may enhance the imaging speed of long lifetime processes such as phosphorescence by several orders of magnitude. PMID:23187477

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinomura, A., E-mail: a.kinomura@aist.go.jp; Suzuki, R.; Oshima, N.

2014-12-15

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at amore » pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO{sub 2} layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.« less

Risks of a lifetime in construction. Part II: Chronic occupational diseases.

PubMed

Ringen, Knut; Dement, John; Welch, Laura; Dong, Xiuwen Sue; Bingham, Eula; Quinn, Patricia S

2014-11-01

We developed working-life estimates of risk for dust-related occupational lung disease, COPD, and hearing loss based on the experience of the Building Trades National Medical Screening Program in order to (1) demonstrate the value of estimates of lifetime risk, and (2) make lifetime risk estimates for common conditions among construction workers. Estimates of lifetime risk were performed based on 12,742 radiographic evaluations, 12,679 spirometry tests, and 11,793 audiograms. Over a 45-year working life, 16% of construction workers developed COPD, 11% developed parenchymal radiological abnormality, and 73.8% developed hearing loss. The risk for occupationally related disease over a lifetime in a construction trade was 2-6 times greater than the risk in non-construction workers. When compared with estimates from annualized cross-sectional data, lifetime risk estimates are highly useful for risk expression, and should help to inform stakeholders in the construction industry as well as policy-makers about magnitudes of risk. © 2014 Wiley Periodicals, Inc.

Multiphoton autofluorescence lifetime imaging of induced pluripotent stem cells

NASA Astrophysics Data System (ADS)

Uchugonova, Aisada

2017-06-01

The multiphoton fluorescence lifetime imaging tomograph MPTflex with its flexible 360-deg scan head, articulated arm, and tunable femtosecond laser source was employed to study induced pluripotent stem cell (iPS) cultures. Autofluorescence (AF) lifetime imaging was performed with 250-ps temporal resolution and submicron spatial resolution using time-correlated single-photon counting. The two-photon excited AF was based on the metabolic coenzymes NAD(P)H and flavin adenine dinucleotide/flavoproteins. iPS cells generated from mouse embryonic fibroblasts (MEFs) and cocultured with growth-arrested MEFs as feeder cells have been studied. Significant differences on AF lifetime signatures were identified between iPS and feeder cells as well as between their differentiating counterparts.

Fatigue reassessment for lifetime extension of offshore wind monopile substructures

NASA Astrophysics Data System (ADS)

Ziegler, Lisa; Muskulus, Michael

2016-09-01

Fatigue reassessment is required to decide about lifetime extension of aging offshore wind farms. This paper presents a methodology to identify important parameters to monitor during the operational phase of offshore wind turbines. An elementary effects method is applied to analyze the global sensitivity of residual fatigue lifetimes to environmental, structural and operational parameters. Therefore, renewed lifetime simulations are performed for a case study which consists of a 5 MW turbine with monopile substructure in 20 m water depth. Results show that corrosion, turbine availability, and turbulence intensity are the most influential parameters. This can vary strongly for other settings (water depth, turbine size, etc.) making case-specific assessments necessary.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirvonen, Liisa M.; Le Marois, Alix; Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk

We perform wide-field time-correlated single photon counting-based fluorescence lifetime imaging (FLIM) with a crossed delay line anode image intensifier, where the pulse propagation time yields the photon position. This microchannel plate-based detector was read out with conventional fast timing electronics and mounted on a fluorescence microscope with total internal reflection (TIR) illumination. The picosecond time resolution of this detection system combines low illumination intensity of microwatts with wide-field data collection. This is ideal for fluorescence lifetime imaging of cell membranes using TIR. We show that fluorescence lifetime images of living HeLa cells stained with membrane dye di-4-ANEPPDHQ exhibit a reducedmore » lifetime near the coverslip in TIR compared to epifluorescence FLIM.« less

Lifetime Measurement in the Yrast Band of 119I

NASA Astrophysics Data System (ADS)

Lobach, Yu. N.; Pasternak, A. A.; Srebrny, J.; Droste, Ch.; Hagemann, G. B.; Juutinen, S.; Morek, T.; Piiparinen, M.; Podsvirova, E. O.; Toermaenen, S.; Starosta, K.; Virtanen, A.; Wasilewski, A. A.

1999-05-01

The lifetime of levels in the yrast band of 119I were measured by DSAM and RDM using the 109Ag (13C,3n) reaction at E=54 MeV. The detailed description of data analysis including the stopping power determination and estimation of side feeding time is given. A modified method of RDM data analysis --- Recoil Distance Doppler Shape Attenuation (RDDSA) is used.

Probabilistic Scenario-based Seismic Risk Analysis for Critical Infrastructures Method and Application for a Nuclear Power Plant

NASA Astrophysics Data System (ADS)

Klügel, J.

2006-12-01

Deterministic scenario-based seismic hazard analysis has a long tradition in earthquake engineering for developing the design basis of critical infrastructures like dams, transport infrastructures, chemical plants and nuclear power plants. For many applications besides of the design of infrastructures it is of interest to assess the efficiency of the design measures taken. These applications require a method allowing to perform a meaningful quantitative risk analysis. A new method for a probabilistic scenario-based seismic risk analysis has been developed based on a probabilistic extension of proven deterministic methods like the MCE- methodology. The input data required for the method are entirely based on the information which is necessary to perform any meaningful seismic hazard analysis. The method is based on the probabilistic risk analysis approach common for applications in nuclear technology developed originally by Kaplan & Garrick (1981). It is based (1) on a classification of earthquake events into different size classes (by magnitude), (2) the evaluation of the frequency of occurrence of events, assigned to the different classes (frequency of initiating events, (3) the development of bounding critical scenarios assigned to each class based on the solution of an optimization problem and (4) in the evaluation of the conditional probability of exceedance of critical design parameters (vulnerability analysis). The advantage of the method in comparison with traditional PSHA consists in (1) its flexibility, allowing to use different probabilistic models for earthquake occurrence as well as to incorporate advanced physical models into the analysis, (2) in the mathematically consistent treatment of uncertainties, and (3) in the explicit consideration of the lifetime of the critical structure as a criterion to formulate different risk goals. The method was applied for the evaluation of the risk of production interruption losses of a nuclear power plant during its residual lifetime.

Radiation Assurance for the Space Environment

NASA Technical Reports Server (NTRS)

Barth, Janet L.; LaBel, Kenneth A.; Poivey, Christian

2004-01-01

The space radiation environment can lead to extremely harsh operating conditions for spacecraft electronic systems. A hardness assurance methodology must be followed to assure that the space radiation environment does not compromise the functionality and performance of space-based systems during the mission lifetime. The methodology includes a definition of the radiation environment, assessment of the radiation sensitivity of parts, worst-case analysis of the impact of radiation effects, and part acceptance decisions which are likely to include mitigation measures.

Applying Energy Conservation Retrofits to Standard Army Buildings: Data Analysis and Recommendations

DTIC Science & Technology

1990-09-01

than mechanical. The line titled "Mechanical" includes all line items related to electrical work, HVAC work, and controls. A 25 pet..ctit mark-up is...criteria specify a life of 15 years for HVAC retrofits and a 25-year life for weatherization, calculations were performed for both lifetimes for...circulation pump was serviced. "• Smaller sized steam valves and actuators were installed in the hot water converters. "* New pneumatic heating reset

Lifetime prediction and reliability estimation methodology for Stirling-type pulse tube refrigerators by gaseous contamination accelerated degradation testing

NASA Astrophysics Data System (ADS)

Wan, Fubin; Tan, Yuanyuan; Jiang, Zhenhua; Chen, Xun; Wu, Yinong; Zhao, Peng

2017-12-01

Lifetime and reliability are the two performance parameters of premium importance for modern space Stirling-type pulse tube refrigerators (SPTRs), which are required to operate in excess of 10 years. Demonstration of these parameters provides a significant challenge. This paper proposes a lifetime prediction and reliability estimation method that utilizes accelerated degradation testing (ADT) for SPTRs related to gaseous contamination failure. The method was experimentally validated via three groups of gaseous contamination ADT. First, the performance degradation model based on mechanism of contamination failure and material outgassing characteristics of SPTRs was established. Next, a preliminary test was performed to determine whether the mechanism of contamination failure of the SPTRs during ADT is consistent with normal life testing. Subsequently, the experimental program of ADT was designed for SPTRs. Then, three groups of gaseous contamination ADT were performed at elevated ambient temperatures of 40 °C, 50 °C, and 60 °C, respectively and the estimated lifetimes of the SPTRs under normal condition were obtained through acceleration model (Arrhenius model). The results show good fitting of the degradation model with the experimental data. Finally, we obtained the reliability estimation of SPTRs through using the Weibull distribution. The proposed novel methodology enables us to take less than one year time to estimate the reliability of the SPTRs designed for more than 10 years.

Attenuated Neural Processing of Risk in Young Adults at Risk for Stimulant Dependence

PubMed Central

Reske, Martina; Stewart, Jennifer L.; Flagan, Taru M.; Paulus, Martin P.

2015-01-01

Objective Approximately 10% of young adults report non-medical use of stimulants (cocaine, amphetamine, methylphenidate), which puts them at risk for the development of dependence. This fMRI study investigates whether subjects at early stages of stimulant use show altered decision making processing. Methods 158 occasional stimulants users (OSU) and 50 comparison subjects (CS) performed a “risky gains” decision making task during which they could select safe options (cash in 20 cents) or gamble them for double or nothing in two consecutive gambles (win or lose 40 or 80 cents, “risky decisions”). The primary analysis focused on risky versus safe decisions. Three secondary analyses were conducted: First, a robust regression examined the effect of lifetime exposure to stimulants and marijuana; second, subgroups of OSU with >1000 (n = 42), or <50 lifetime marijuana uses (n = 32), were compared to CS with <50 lifetime uses (n = 46) to examine potential marijuana effects; third, brain activation associated with behavioral adjustment following monetary losses was probed. Results There were no behavioral differences between groups. OSU showed attenuated activation across risky and safe decisions in prefrontal cortex, insula, and dorsal striatum, exhibited lower anterior cingulate cortex (ACC) and dorsal striatum activation for risky decisions and greater inferior frontal gyrus activation for safe decisions. Those OSU with relatively more stimulant use showed greater dorsal ACC and posterior insula attenuation. In comparison, greater lifetime marijuana use was associated with less neural differentiation between risky and safe decisions. OSU who chose more safe responses after losses exhibited similarities with CS relative to those preferring risky options. Discussion Individuals at risk for the development of stimulant use disorders presented less differentiated neural processing of risky and safe options. Specifically, OSU show attenuated brain response in regions critical for performance monitoring, reward processing and interoceptive awareness. Marijuana had additive effects by diminishing neural risk differentiation. PMID:26076493

Long-term performance analysis of CIGS thin-film PV modules

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.; Kaul, Ashwani; Pethe, Shirish A.

2011-09-01

Current accelerated qualification tests of photovoltaic (PV) modules mostly assist in avoiding infant mortality but can neither duplicate changes occurring in the field nor can predict useful lifetime. Therefore, outdoor monitoring of fielddeployed thin-film PV modules was undertaken at FSEC with goals of assessing their performance in hot and humid climate under high system voltage operation and to correlate the PV performance with the meteorological parameters. Significant and comparable degradation rate of -5.13% and -4.5% per year was found by PV USA type regression analysis for the positive and negative strings respectively of 40W glass-to-glass CIGS thin-film PV modules in the hot and humid climate of Florida. With the current-voltage measurements it was found that the performance degradation within the PV array was mainly due to a few (8-12%) modules having a substantially high degradation. The remaining modules within the array continued to show reasonable performance (>96% of the rated power after ~ 4years).

Dynamic Modeling, Model-Based Control, and Optimization of Solid Oxide Fuel Cells

NASA Astrophysics Data System (ADS)

Spivey, Benjamin James

2011-07-01

Solid oxide fuel cells are a promising option for distributed stationary power generation that offers efficiencies ranging from 50% in stand-alone applications to greater than 80% in cogeneration. To advance SOFC technology for widespread market penetration, the SOFC should demonstrate improved cell lifetime and load-following capability. This work seeks to improve lifetime through dynamic analysis of critical lifetime variables and advanced control algorithms that permit load-following while remaining in a safe operating zone based on stress analysis. Control algorithms typically have addressed SOFC lifetime operability objectives using unconstrained, single-input-single-output control algorithms that minimize thermal transients. Existing SOFC controls research has not considered maximum radial thermal gradients or limits on absolute temperatures in the SOFC. In particular, as stress analysis demonstrates, the minimum cell temperature is the primary thermal stress driver in tubular SOFCs. This dissertation presents a dynamic, quasi-two-dimensional model for a high-temperature tubular SOFC combined with ejector and prereformer models. The model captures dynamics of critical thermal stress drivers and is used as the physical plant for closed-loop control simulations. A constrained, MIMO model predictive control algorithm is developed and applied to control the SOFC. Closed-loop control simulation results demonstrate effective load-following, constraint satisfaction for critical lifetime variables, and disturbance rejection. Nonlinear programming is applied to find the optimal SOFC size and steady-state operating conditions to minimize total system costs.

Theory of Positron Annihilation in Helium-Filled Bubbles in Plutonium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sterne, P A; Pask, J E

2003-02-13

Positron annihilation lifetime spectroscopy is a sensitive probe of vacancies and voids in materials. This non-destructive measurement technique can identify the presence of specific defects in materials at the part-per-million level. Recent experiments by Asoka-Kumar et al. have identified two lifetime components in aged plutonium samples--a dominant lifetime component of around 182 ps and a longer lifetime component of around 350-400ps. This second component appears to increase with the age of the sample, and accounts for only about 5 percent of the total intensity in 35 year-old plutonium samples. First-principles calculations of positron lifetimes are now used extensively to guidemore » the interpretation of positron lifetime data. At Livermore, we have developed a first-principles finite-element-based method for calculating positron lifetimes for defects in metals. This method is capable of treating system cell sizes of several thousand atoms, allowing us to model defects in plutonium ranging in size from a mono-vacancy to helium-filled bubbles of over 1 nm in diameter. In order to identify the defects that account for the observed lifetime values, we have performed positron lifetime calculations for a set of vacancies, vacancy clusters, and helium-filled vacancy clusters in delta-plutonium. The calculations produced values of 143ps for defect-free delta-Pu and 255ps for a mono-vacancy in Pu, both of which are inconsistent with the dominant experimental lifetime component of 182ps. Larger vacancy clusters have even longer lifetimes. The observed positron lifetime is significantly shorter than the calculated lifetimes for mono-vacancies and larger vacancy clusters, indicating that open vacancy clusters are not the dominant defect in the aged plutonium samples. When helium atoms are introduced into the vacancy cluster, the positron lifetime is reduced due to the increased density of electrons available for annihilation. For a mono-vacancy in Pu containing one helium atom, the calculated lifetime is 190 ps, while a di-vacancy containing two helium atoms has a positron lifetime of 205 ps. In general, increasing the helium density in a vacancy cluster or He-filled bubble reduces the positron lifetime, so that the same lifetime value can arise fi-om a range of vacancy cluster sizes with different helium densities. In order to understand the variation of positron lifetime with vacancy cluster size and helium density in the defect, we have performed over 60 positron lifetime calculations with vacancy cluster sizes ranging from 1 to 55 vacancies and helium densities ranging fi-om zero to five helium atoms per vacancy. The results indicate that the experimental lifetime of 182 ps is consistent with the theoretical value of 190 ps for a mono-vacancy with a single helium atom, but that slightly better agreement is obtained for larger clusters of 6 or more vacancies containing 2-3 helium atoms per vacancy. For larger vacancy clusters with diameters of about 3-5 nm or more, the annihilation with helium electrons dominates the positron annihilation rate; the observed lifetime of 180ps is then consistent with a helium concentration in the range of 3 to 3.5 Hehacancy, setting an upper bound on the helium concentration in the vacancy clusters. In practice, the single lifetime component is most probably associated with a family of helium-filled bubbles rather than with a specific unique defect size. The longer 350-400ps lifetime component is consistent with a relatively narrow range of defect sizes and He concentration. At zero He concentration, the lifetime values are matched by small vacancy clusters containing 6-12 vacancies. With increasing vacancy cluster size, a small amount of He is required to keep the lifetime in the 350-400 ps range, until the value saturates for larger helium bubbles of more than 50 vacancies (bubble diameter > 1.3 nm) at a helium concentration close to 1 He/vacancy. These results, taken together with the experimental data, indicate that the features observed in TEM data by Schwartz et al are not voids, but are in fact helium-filled bubbles with a helium pressure of around 2-3 helium atoms per vacancy, depending on the bubble size. This is consistent with the conclusions of recently developed models of He-bubble growth in aged plutonium.« less

Nanoporous Tin with a Granular Hierarchical Ligament Morphology as a Highly Stable Li-Ion Battery Anode

DOE PAGES

Cook, John B.; Detsi, Eric; Liu, Yijin; ...

2016-12-07

Next generation Li-ion batteries will require negative electrode materials with energy densities many-fold higher than that found in the graphitic carbon currently used in commercial Li-ion batteries. While various nanostructured alloying-type anode materials may satisfy that requirement, such materials do not always exhibit long cycle lifetimes and/or their processing routes are not always suitable for large-scale synthesis. Here, we report on a high-performance anode material for next generation Li-ion batteries made of nanoporous Sn powders with hierarchical ligament morphology. This material system combines both long cycle lifetimes (more than 72% capacity retention after 350 cycles), high capacity (693 mAh/g, nearlymore » twice that of commercial graphitic carbon), good charging/discharging capabilities (545 mAh/g at 1 A/g, 1.5C), and a scalable processing route that involves selective alloy corrosion. The good cycling performance of this system is attributed to its nanoporous architecture and its unique hierarchical ligament morphology, which accommodates the large volume changes taking place during lithiation, as confirmed by synchrotron-based ex-situ X-ray 3D tomography analysis. In conclusion, our findings are an important step for the development of high-performance Li-ion batteries.« less

An On-Demand Emergency Packet Transmission Scheme for Wireless Body Area Networks.

PubMed

Al Ameen, Moshaddique; Hong, Choong Seon

2015-12-04

The rapid developments of sensor devices that can actively monitor human activities have given rise to a new field called wireless body area network (BAN). A BAN can manage devices in, on and around the human body. Major requirements of such a network are energy efficiency, long lifetime, low delay, security, etc. Traffic in a BAN can be scheduled (normal) or event-driven (emergency). Traditional media access control (MAC) protocols use duty cycling to improve performance. A sleep-wake up cycle is employed to save energy. However, this mechanism lacks features to handle emergency traffic in a prompt and immediate manner. To deliver an emergency packet, a node has to wait until the receiver is awake. It also suffers from overheads, such as idle listening, overhearing and control packet handshakes. An external radio-triggered wake up mechanism is proposed to handle prompt communication. It can reduce the overheads and improve the performance through an on-demand scheme. In this work, we present a simple-to-implement on-demand packet transmission scheme by taking into considerations the requirements of a BAN. The major concern is handling the event-based emergency traffic. The performance analysis of the proposed scheme is presented. The results showed significant improvements in the overall performance of a BAN compared to state-of-the-art protocols in terms of energy consumption, delay and lifetime.

An On-Demand Emergency Packet Transmission Scheme for Wireless Body Area Networks

PubMed Central

Al Ameen, Moshaddique; Hong, Choong Seon

2015-01-01

The rapid developments of sensor devices that can actively monitor human activities have given rise to a new field called wireless body area network (BAN). A BAN can manage devices in, on and around the human body. Major requirements of such a network are energy efficiency, long lifetime, low delay, security, etc. Traffic in a BAN can be scheduled (normal) or event-driven (emergency). Traditional media access control (MAC) protocols use duty cycling to improve performance. A sleep-wake up cycle is employed to save energy. However, this mechanism lacks features to handle emergency traffic in a prompt and immediate manner. To deliver an emergency packet, a node has to wait until the receiver is awake. It also suffers from overheads, such as idle listening, overhearing and control packet handshakes. An external radio-triggered wake up mechanism is proposed to handle prompt communication. It can reduce the overheads and improve the performance through an on-demand scheme. In this work, we present a simple-to-implement on-demand packet transmission scheme by taking into considerations the requirements of a BAN. The major concern is handling the event-based emergency traffic. The performance analysis of the proposed scheme is presented. The results showed significant improvements in the overall performance of a BAN compared to state-of-the-art protocols in terms of energy consumption, delay and lifetime. PMID:26690161

FastFLIM, the all-in-one engine for measuring photoluminescence lifetime of 100 picoseconds to 100 milliseconds

NASA Astrophysics Data System (ADS)

Sun, Yuansheng; Coskun, Ulas; Liao, Shih-Chu Jeff; Barbieri, Beniamino

2018-02-01

Photoluminescence (PL) refers to light emission initiated by any form of photon excitation. PL spectroscopy and microscopy imaging has been widely applied in material, chemical and life sciences. Measuring its lifetime yields a new dimension of the PL imaging and opens new opportunities for many PL applications. In solar cell research, quantification of the PL lifetime has become an important evaluation for the characteristics of the Perovskite thin film. Depending upon the PL process (fluorescence, phosphorescence, photon upconversion, etc.), the PL lifetimes to be measured can vary in a wide timescale range (e.g. from sub-nanoseconds to microseconds or even milliseconds) - it is challenging to cover this wide range of lifetime measurements by a single technique efficiently. Here, we present a novel digital frequency domain (DFD) technique named FastFLIM, capable of measuring the PL lifetime from 100 ps to 100 ms at the high data collection efficiency (up to 140-million counts per second). Other than the traditional nonlinear leastsquare fitting analysis, the raw data acquired by FastFLIM can be directly processed by the model-free phasor plots approach for instant and unbiased lifetime results, providing the ideal routine for the PL lifetime microscopy imaging.

Bayes Analysis and Reliability Implications of Stress-Rupture Testing a Kevlar/Epoxy COPV Using Temperature and Pressure Acceleration

NASA Technical Reports Server (NTRS)

Phoenix, S. Leigh; Kezirian, Michael T.; Murthy, Pappu L. N.

2009-01-01

Composite Overwrapped Pressure Vessels (COPVs) that have survived a long service time under pressure generally must be recertified before service is extended. Flight certification is dependent on the reliability analysis to quantify the risk of stress rupture failure in existing flight vessels. Full certification of this reliability model would require a statistically significant number of lifetime tests to be performed and is impractical given the cost and limited flight hardware for certification testing purposes. One approach to confirm the reliability model is to perform a stress rupture test on a flight COPV. Currently, testing of such a Kevlar49 (Dupont)/epoxy COPV is nearing completion. The present paper focuses on a Bayesian statistical approach to analyze the possible failure time results of this test and to assess the implications in choosing between possible model parameter values that in the past have had significant uncertainty. The key uncertain parameters in this case are the actual fiber stress ratio at operating pressure, and the Weibull shape parameter for lifetime; the former has been uncertain due to ambiguities in interpreting the original and a duplicate burst test. The latter has been uncertain due to major differences between COPVs in the database and the actual COPVs in service. Any information obtained that clarifies and eliminates uncertainty in these parameters will have a major effect on the predicted reliability of the service COPVs going forward. The key result is that the longer the vessel survives, the more likely the more optimistic stress ratio model is correct. At the time of writing, the resulting effect on predicted future reliability is dramatic, increasing it by about one "nine," that is, reducing the predicted probability of failure by an order of magnitude. However, testing one vessel does not change the uncertainty on the Weibull shape parameter for lifetime since testing several vessels would be necessary.

Effects of ionic liquids on the performance of IPMC

NASA Astrophysics Data System (ADS)

Kim, Min Jung; Park, Sang Woo; Won, Joohye; Nah, Changwoon

2017-04-01

One of the issues in operating the IPMC actuators in air condition is the limited lifetime due to the evaporation of aqueous electrolytes like water. Several attempts were already made for solving the problem using an ionic liquid (IL) with higher boiling point. In this study, three different ILs having similar boiling point but different molecular weight were employed in the IPMC actuators. The actuation performance, notably speed and lifetime, were measured and they are compared with that of water-based IPMC actuator. The lower molecular weight IL showed a comparable actuation speed of water due to faster movement of the ion cluster. The lifetime of the water-based IPMC actuator was found to be only 3 hr. However, the IL-based IPMC actuators showed much improved service life.

Effects of Lifetime Occupational Pesticide Exposure on Postural Control Among Farmworkers and Non-Farmworkers.

PubMed

Sunwook, Kim; Nussbaum, Maury A; Quandt, Sara A; Laurienti, Paul J; Arcury, Thomas A

2016-02-01

The aim of the study was to assess potential chronic effects of pesticide exposure on postural control, by examining postural balance of farmworkers and non-farmworkers diverse self-reported lifetime exposures. Balance was assessed during quiet upright stance under four experimental conditions (2 visual × 2 cognitive difficulty). Significant differences in baseline balance performance (eyes open without cognitive task) between occupational groups were apparent in postural sway complexity. When adding a cognitive task to the eyes open condition, the influence of lifetime exposure on complexity ratios appeared different between occupational groups. Removing visual information revealed a negative association of lifetime exposure with complexity ratios. Farmworkers and non-farmworkers may use different postural control strategies even when controlling for the level of lifetime pesticide exposure. Long-term exposure can affect somatosensory/vestibular sensory systems and the central processing of sensory information for postural control.

Effects of lifetime occupational pesticide exposure on postural control among farmworkers and non-farmworkers

PubMed Central

Sunwook, Kim; Nussbaum, Maury A.; Quandt, Sara A.; Laurienti, Paul J.; Arcury, Thomas A.

2015-01-01

Objective Assess potential chronic effects of pesticide exposure on postural control, by examining postural balance of farmworkers and non-farmworkers diverse self-reported lifetime exposures. Methods Balance was assessed during quiet upright stance under four experimental conditions (2 visual × 2 cognitive difficulty). Results Significant differences in baseline balance performance (eyes open without cognitive task) between occupational groups were apparent in postural sway complexity. When adding a cognitive task to the eyes open condition, the influence of lifetime exposure on complexity ratios appeared different between occupational groups. Removing visual information revealed a negative association of lifetime exposure with complexity ratios. Conclusions Farmworkers and non-farmworkers may use different postural control strategies even when controlling for the level of lifetime pesticide exposure. Long-term exposure can affect somatosensory/vestibular sensory systems and the central processing of sensory information for postural control. PMID:26849257

Positron lifetime setup based on DRS4 evaluation board

NASA Astrophysics Data System (ADS)

Petriska, M.; Sojak, S.; Slugeň, V.

2014-04-01

A digital positron lifetime setup based on DRS4 evaluation board designed at the Paul Scherrer Institute has been constructed and tested in the Positron annihilation laboratory Slovak University of Technology Bratislava. The high bandwidth, low power consumption and short readout time make DRS4 chip attractive for positron annihilation lifetime (PALS) setup, replacing traditional ADCs and TDCs. A software for PALS setup online and offline pulse analysis was developed with Qt,Qwt and ALGLIB libraries.

Assessing the impact of nuclear retirements on the U.S. power sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richards, James; Cole, Wesley J.

This work utilizes the Regional Energy Deployment System (ReEDS) model to analyze the impacts of four nuclear retirement scenarios of the U.S. electricity sector, from nuclear plant lifetimes of 50 to 80 years. The analysis finds that longer nuclear lifetimes decrease the amount of renewable and natural gas capacity. Longer nuclear lifetimes also resulted in lower cumulative and annual carbon emissions, lower transmission builds, and higher energy curtailment and water usage.

Exits in order: How crowding affects particle lifetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penington, Catherine J.; Simpson, Matthew J.; Baker, Ruth E.

2016-06-28

Diffusive processes are often represented using stochastic random walk frameworks. The amount of time taken for an individual in a random walk to intersect with an absorbing boundary is a fundamental property that is often referred to as the particle lifetime, or the first passage time. The mean lifetime of particles in a random walk model of diffusion is related to the amount of time required for the diffusive process to reach a steady state. Mathematical analysis describing the mean lifetime of particles in a standard model of diffusion without crowding is well known. However, the lifetime of agents inmore » a random walk with crowding has received much less attention. Since many applications of diffusion in biology and biophysics include crowding effects, here we study a discrete model of diffusion that incorporates crowding. Using simulations, we show that crowding has a dramatic effect on agent lifetimes, and we derive an approximate expression for the mean agent lifetime that includes crowding effects. Our expression matches simulation results very well, and highlights the importance of crowding effects that are sometimes overlooked.« less

Empirical membrane lifetime model for heavy duty fuel cell systems

NASA Astrophysics Data System (ADS)

Macauley, Natalia; Watson, Mark; Lauritzen, Michael; Knights, Shanna; Wang, G. Gary; Kjeang, Erik

2016-12-01

Heavy duty fuel cells used in transportation system applications such as transit buses expose the fuel cell membranes to conditions that can lead to lifetime-limiting membrane failure via combined chemical and mechanical degradation. Highly durable membranes and reliable predictive models are therefore needed in order to achieve the ultimate heavy duty fuel cell lifetime target of 25,000 h. In the present work, an empirical membrane lifetime model was developed based on laboratory data from a suite of accelerated membrane durability tests. The model considers the effects of cell voltage, temperature, oxygen concentration, humidity cycling, humidity level, and platinum in the membrane using inverse power law and exponential relationships within the framework of a general log-linear Weibull life-stress statistical distribution. The obtained model is capable of extrapolating the membrane lifetime from accelerated test conditions to use level conditions during field operation. Based on typical conditions for the Whistler, British Columbia fuel cell transit bus fleet, the model predicts a stack lifetime of 17,500 h and a membrane leak initiation time of 9200 h. Validation performed with the aid of a field operated stack confirmed the initial goal of the model to predict membrane lifetime within 20% of the actual operating time.

Laser induced fluorescence lifetime characterization of Bacillus endospore species using time correlated single photon counting analysis with the multi-exponential fit method

NASA Astrophysics Data System (ADS)

Smith, Clint; Edwards, Jarrod; Fisher, Andmorgan

2010-04-01

Rapid detection of biological material is critical for determining presence/absence of bacterial endospores within various investigative programs. Even more critical is that if select material tests positive for bacillus endospores then tests should provide data at the species level. Optical detection of microbial endospore formers such as Bacillus sp. can be heavy, cumbersome, and may only identify at the genus level. Data provided from this study will aid in characterization needed by future detection systems for further rapid breakdown analysis to gain insight into a more positive signature collection of Bacillus sp. Literature has shown that fluorescence spectroscopy of endospores could be statistically separated from other vegetative genera, but could not be separated among one another. Results of this study showed endospore species separation is possible using laser-induce fluorescence with lifetime decay analysis for Bacillus endospores. Lifetime decays of B. subtilis, B. megaterium, B. coagulans, and B. anthracis Sterne strain were investigated. Using the Multi-Exponential fit method data showed three distinct lifetimes for each species within the following ranges, 0.2-1.3 ns; 2.5-7.0 ns; 7.5-15.0 ns, when laser induced at 307 nm. The four endospore species were individually separated using principle component analysis (95% CI).

Rapid Analysis, Self-Calibrating Array for Air Monitoring

NASA Technical Reports Server (NTRS)

Homer, Margie L.; Shevade, Abhijit V.; Lara, Liana; Huerta, Ramon; Vergara, Alexander; Muezzinoglua, Mehmet K.

2012-01-01

Human space missions have critical needs for monitoring and control for life support systems. These systems have monitoring needs that include feedback for closed loop processes and quality control for environmental factors. Sensors and monitoring technologies assure that the air environment and water supply for the astronaut crew habitat fall within acceptable limits, and that the life support system is functioning properly and efficiently. The longer the flight duration and the more distant the destination, the more critical it becomes to have carefully monitored and automated control systems for life support. Past experiments with the JPL ENose have demonstrated a lifetime of the sensor array, with the software, of around 18 months. The lifetime of the calibration, for some analytes, was as long as 24 months. We are working on a sensor array and new algorithms that will include sensor response time in the analysis. The preliminary array analysis for two analytes shows that the analysis time, of an event, can be dropped from 45 minutes to less than10 minutes and array training time can be cut substantially. We will describe the lifetime testing of an array and show lifetime data on individual sensors. This progress will lead to more rapid identification of analytes, and faster training time of the array.

Domestic labour, paid employment and women's health: analysis of life course data.

PubMed

Blane, D; Berney, L; Montgomery, S M

2001-03-01

The relationship between the amount of domestic labour performed by a woman during her lifetime and a variety of self-reported and objective measures of her health in early old age was examined in the female members (n = 155) of a data set containing considerable life course information, including full household, residential and occupational histories. Domestic labour, on its own, proved a weak predictor of health. The relationship strengthened when domestic labour was combined with the hazards of the formal paid employment which the woman had performed. This suggests that it is the combination of domestic labour plus paid employment which influences women's health. The robustness of this conclusion is indicated by its agreement with other studies which reached the same conclusion through an analysis of data with markedly different characteristics.

Lifetime prediction for the subsurface crack propagation using three-dimensional dynamic FEA model

NASA Astrophysics Data System (ADS)

Yin, Yuan; Chen, Yun-Xia; Liu, Le

2017-03-01

The subsurface crack propagation is one of the major interests for gear system research. The subsurface crack propagation lifetime is the number of cycles remaining for a spall to appear, which can be obtained through either stress intensity factor or accumulated plastic strain analysis. In this paper, the heavy loads are applied to the gear system. When choosing stress intensity factor, the high compressive stress suppresses Mode I stress intensities and severely reduces Mode II stress intensities in the heavily loaded lubricated contacts. Such that, the accumulated plastic strain is selected to calculate the subsurface crack propagation lifetime from the three-dimensional FEA model through ANSYS Workbench transient analysis. The three-dimensional gear FEA dynamic model with the subsurface crack is built through dividing the gears into several small elements. The calculation of the total cycles of the elements is proposed based on the time-varying accumulated plastic strain, which then will be used to calculate the subsurface crack propagation lifetime. During this process, the demonstration from a subsurface crack to a spall can be uncovered. In addition, different sizes of the elements around the subsurface crack are compared in this paper. The influences of the frictional coefficient and external torque on the crack propagation lifetime are also discussed. The results show that the lifetime of crack propagation decreases significantly when the external load T increasing from 100 N m to 150 N m. Given from the distributions of the accumulated plastic strain, the lifetime shares no significant difference when the frictional coefficient f ranging in 0.04-0.06.

Progress in the RAMI analysis of a conceptual LHCD system for DEMO

NASA Astrophysics Data System (ADS)

Mirizzi, F.

2014-02-01

Reliability, Availability, Maintainability and Inspectability (RAMI) concepts and techniques, that acquired great importance during the first manned space missions, have been progressively extended to industrial, scientific and consumer equipments to assure them satisfactory performances and lifetimes. In the design of experimental facilities, like tokamaks, mainly aimed at demonstrating validity and feasibility of scientific theories, RAMI analysis has been often left aside. DEMO, the future prototype fusion reactors, will be instead designed for steadily delivering electrical energy to commercial grids, so that the RAMI aspects will assume an absolute relevance since their initial design phases. A preliminary RAMI analysis of the LHCD system for the conceptual EU DEMO reactor is given in the paper.

Comparison of efficiency degradation in polycrystalline-Si and CdTe thin-film PV modules via accelerated lifecycle testing

NASA Astrophysics Data System (ADS)

Lai, T.; Potter, B. G.; Simmons-Potter, K.

2017-08-01

Thin-film solar cells normally have the shortest energy payback time due to their simpler mass-production process compared to polycrystalline-Si photovoltaic (PV) modules, despite the fact that crystalline-Si-based technology typically has a longer total lifetime and a higher initial power conversion efficiency. For both types of modules, significant aging occurs during the first two years of usage with slower long-term aging over the module lifetime. The PV lifetime and the return-on-investment for local PV system installations rely on long-term device performance. Understanding the efficiency degradation behavior under a given set of environmental conditions is, therefore, a primary goal for experimental research and economic analysis. In the present work, in-situ measurements of key electrical characteristics (J, V, Pmax, etc.) in polycrystalline-Si and CdTe thin-film PV modules have been analyzed. The modules were subjected to identical environmental conditions, representative of southern Arizona, in a full-scale, industrial-standard, environmental degradation chamber, equipped with a single-sun irradiance source, temperature, and humidity controls, and operating an accelerated lifecycle test (ALT) sequence. Initial results highlight differences in module performance with environmental conditions, including temperature de-rating effects, for the two technologies. Notably, the thin-film CdTe PV module was shown to be approximately 15% less sensitive to ambient temperature variation. After exposure to a seven-month equivalent compressed night-day weather cycling regimen the efficiency degradation rates of both PV technology types were obtained and will be discussed.

Cathodic Electrodeposition of Ni-Mo on Semiconducting NiFe2 O4 for Photoelectrochemical Hydrogen Evolution in Alkaline Media.

PubMed

Wijten, Jochem H J; Jong, Ronald P H; Mul, Guido; Weckhuysen, Bert M

2018-04-25

Photocathodes for hydrogen evolution from water were made by electrodeposition of Ni-Mo layers on NiFe 2 O 4 substrates, deposited by spin coating on F:SnO 2 -glass. Analysis confirmed the formation of two separate layers, without significant reduction of NiFe 2 O 4 . Bare NiFe 2 O 4 was found to be unstable under alkaline conditions during (photo)electrochemistry. To improve the stability significantly, the deposition of a bifunctional Ni-Mo layer through a facile electrodeposition process was performed and the composite electrodes showed stable operation for at least 1 h. Moreover, photocurrents up to -2.1 mA cm -2 at -0.3 V vs. RHE were obtained for Ni-Mo/NiFe 2 O 4 under ambient conditions, showing that the new combination functions as both a stabilizing and catalytic layer for the photoelectrochemical evolution of hydrogen. The photoelectrochemical response of these composite electrodes decreased with increasing NiFe 2 O 4 layer thickness. Transient absorption spectroscopy showed that the lifetime of excited states is short and on the ns timescale. An increase in lifetime was observed for NiFe 2 O 4 of large layer thickness, likely explained by decreasing the defect density in the primary layer(s), as a result of repetitive annealing at elevated temperature. The photoelectrochemical and transient absorption spectroscopy results indicated that a short charge carrier lifetime limits the performance of Ni-Mo/NiFe 2 O 4 photocathodes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Late-Life Depressive Symptoms and Lifetime History of Major Depression: Cognitive Deficits are Largely Due to Incipient Dementia rather than Depression.

PubMed

Heser, Kathrin; Bleckwenn, Markus; Wiese, Birgitt; Mamone, Silke; Riedel-Heller, Steffi G; Stein, Janine; Lühmann, Dagmar; Posselt, Tina; Fuchs, Angela; Pentzek, Michael; Weyerer, Siegfried; Werle, Jochen; Weeg, Dagmar; Bickel, Horst; Brettschneider, Christian; König, Hans-Helmut; Maier, Wolfgang; Scherer, Martin; Wagner, Michael

2016-08-01

Late-life depression is frequently accompanied by cognitive impairments. Whether these impairments indicate a prodromal state of dementia, or are a symptomatic expression of depression per se is not well-studied. In a cohort of very old initially non-demented primary care patients (n = 2,709, mean age = 81.1 y), cognitive performance was compared between groups of participants with or without elevated depressive symptoms and with or without subsequent dementia using ANCOVA (adjusted for age, sex, and education). Logistic regression analyses were computed to predict subsequent dementia over up to six years of follow-up. The same analytical approach was performed for lifetime major depression. Participants with elevated depressive symptoms without subsequent dementia showed only small to medium cognitive deficits. In contrast, participants with depressive symptoms with subsequent dementia showed medium to very large cognitive deficits. In adjusted logistic regression models, learning and memory deficits predicted the risk for subsequent dementia in participants with depressive symptoms. Participants with a lifetime history of major depression without subsequent dementia showed no cognitive deficits. However, in adjusted logistic regression models, learning and orientation deficits predicted the risk for subsequent dementia also in participants with lifetime major depression. Marked cognitive impairments in old age depression should not be dismissed as "depressive pseudodementia", but require clinical attention as a possible sign of incipient dementia. Non-depressed elderly with a lifetime history of major depression, who remained free of dementia during follow-up, had largely normal cognitive performance.

Enhancing the sensitivity of fluorescence correlation spectroscopy by using time-correlated single photon counting.

PubMed

Lamb, D C; Müller, B K; Bräuchle, C

2005-10-01

Fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS) are methods that extract information about a sample from the influence of thermodynamic equilibrium fluctuations on the fluorescence intensity. This method allows dynamic information to be obtained from steady state equilibrium measurements and its popularity has dramatically increased in the last 10 years due to the development of high sensitivity detectors and its combination with confocal microscopy. Using time-correlated single-photon counting (TCSPC) detection and pulsed excitation, information over the duration of the excited state can be extracted and incorporated in the analysis. In this short review, we discuss new methodologies that have recently emerged which incorporated fluorescence lifetime information or TCSPC data in the FCS and FCCS analysis. Time-gated FCS discriminates between which photons are to be incorporated in the analysis dependent upon their arrival time after excitation. This allows for accurate FCS measurements in the presence of fluorescent background, determination of sample homogeneity, and the ability to distinguish between static and dynamic heterogeneities. A similar method, time-resolved FCS can be used to resolve the individual correlation functions from multiple fluorophores through the different fluorescence lifetimes. Pulsed interleaved excitation (PIE) encodes the excitation source into the TCSPC data. PIE can be used to perform dual-channel FCCS with a single detector and allows elimination of spectral cross-talk with dual-channel detection. For samples that undergo fluorescence resonance energy transfer (FRET), quantitative FCCS measurements can be performed in spite of the FRET and the static FRET efficiency can be determined.

Predicting a future lifetime through Box-Cox transformation.

PubMed

Yang, Z

1999-09-01

In predicting a future lifetime based on a sample of past lifetimes, the Box-Cox transformation method provides a simple and unified procedure that is shown in this article to meet or often outperform the corresponding frequentist solution in terms of coverage probability and average length of prediction intervals. Kullback-Leibler information and second-order asymptotic expansion are used to justify the Box-Cox procedure. Extensive Monte Carlo simulations are also performed to evaluate the small sample behavior of the procedure. Certain popular lifetime distributions, such as Weibull, inverse Gaussian and Birnbaum-Saunders are served as illustrative examples. One important advantage of the Box-Cox procedure lies in its easy extension to linear model predictions where the exact frequentist solutions are often not available.

Evolution of collectivity in the N =100 isotones near 170Yb

NASA Astrophysics Data System (ADS)

Karayonchev, V.; Régis, J.-M.; Jolie, J.; Blazhev, A.; Altenkirch, R.; Ansari, S.; Dannhoff, M.; Diel, F.; Esmaylzadeh, A.; Fransen, C.; Gerst, R.-B.; Moschner, K.; Müller-Gatermann, C.; Saed-Samii, N.; Stegemann, S.; Warr, N.; Zell, K. O.

2017-03-01

An experiment using the electronic γ -γ fast-timing technique was performed to measure lifetimes of the yrast states in 170Yb. The lifetime of the yrast 2+ state was determined using the slope method. The value of τ =2.33 (3 ) ns is in good agreement with the lifetimes measured using other techniques. The lifetimes of the first 4+ and 6+ states are determined using the generalized centroid difference method. The derived B (E 2 ) values are compared to calculations done using the confined beta soft model and show good agreement with the experimental values. These calculations were extended to the isotonic chain N =100 around 170Yb and show a good quantitative description of the collectivity observed along it.

Progress toward a new beam measurement of the neutron lifetime

NASA Astrophysics Data System (ADS)

Hoogerheide, Shannon Fogwell

2016-09-01

Neutron beta decay is the simplest example of nuclear beta decay. A precise value of the neutron lifetime is important for consistency tests of the Standard Model and Big Bang Nucleosysnthesis models. The beam neutron lifetime method requires the absolute counting of the decay protons in a neutron beam of precisely known flux. Recent work has resulted in improvements in both the neutron and proton detection systems that should permit a significant reduction in systematic uncertainties. A new measurement of the neutron lifetime using the beam method will be performed at the National Institute of Standards and Technology Center for Neutron Research. The projected uncertainty of this new measurement is 1 s. An overview of the measurement and the technical improvements will be discussed.

Utility of positron annihilation lifetime technique for the assessment of spectroscopic data of some charge-transfer complexes derived from N-(1-Naphthyl)ethylenediamine dihydrochloride

NASA Astrophysics Data System (ADS)

Refat, Moamen S.; Adam, Abdel Majid A.; Sharshar, T.; Saad, Hosam A.; Eldaroti, Hala H.

2014-03-01

In this work, structural, thermal, morphological, pharmacological screening and positron annihilation lifetime measurements were performed on the interactions between a N-(1-Naphthyl)ethylenediamine dihydrochloride (NEDA·2HCl) donor and three types of acceptors to characterize these CT complexes. The three types of acceptors include π-acceptors (quinol and picric acid), σ-acceptors (iodine) and vacant orbital acceptors (tin(IV) tetrachloride and zinc chloride). The positron annihilation lifetime parameters were found to be dependent on the structure, electronic configuration, the power of acceptors and molecular weight of the CT complexes. The positron annihilation lifetime spectroscopy can be used as a probe for the formation of charge-transfer (CT) complexes.

Energy reduction for the spot welding process in the automotive industry

NASA Astrophysics Data System (ADS)

Cullen, J. D.; Athi, N.; Al-Jader, M. A.; Shaw, A.; Al-Shamma'a, A. I.

2007-07-01

When performing spot welding on galvanised metals, higher welding force and current are required than on uncoated steels. This has implications for the energy usage when creating each spot weld, of which there are approximately 4300 in each passenger car. The paper presented is an overview of electrode current selection and its variance over the lifetime of the electrode tip. This also describes the proposed analysis system for the selection of welding parameters for the spot welding process, as the electrode tip wears.

A sensitivity analysis of central flat-plate photovoltaic systems and implications for national photovoltaics program planning

NASA Technical Reports Server (NTRS)

Crosetti, M. R.

1985-01-01

The sensitivity of the National Photovoltaic Research Program goals to changes in individual photovoltaic system parameters is explored. Using the relationship between lifetime cost and system performance parameters, tests were made to see how overall photovoltaic system energy costs are affected by changes in the goals set for module cost and efficiency, system component costs and efficiencies, operation and maintenance costs, and indirect costs. The results are presented in tables and figures for easy reference.

Dynamic fatigue of a lithia-alumina-silica glass-ceramic

NASA Technical Reports Server (NTRS)

Tucker, Dennis S.

1990-01-01

A dynamic fatigue study was performed on a Li2O-Al2O3-SiO2 glass-ceramic in order to assess its susceptibility to delayed failure. Fracture mechanics techniques were used to analyze the results for the purpose of making lifetime predictions for optical elements made from this material. The material has reasonably good resistance (N = 20) to stress corrosion in ambient conditions. Analysis also indicated the elements should survive applied stresses incurred during grinding and polishing operations.

Heat storage capability of a rolling cylinder using Glauber's salt

NASA Technical Reports Server (NTRS)

Herrick, C. S.; Zarnoch, K. P.

1980-01-01

The rolling cylinder phase change heat storage concept was developed to the point where a prototype design is completed and a cost analysis is prepared. A series of experimental and analytical tasks are defined to establish the thermal, mechanical, and materials behavior of rolling cylinder devices. These tasks include: analyses of internal and external heat transfer; performance and lifetime testing of the phase change materials; corrosion evaluation; development of a mathematical model; and design of a prototype and associated test equipment.

Digitally synthesized beat frequency-multiplexed fluorescence lifetime spectroscopy

PubMed Central

Chan, Jacky C. K.; Diebold, Eric D.; Buckley, Brandon W.; Mao, Sien; Akbari, Najva; Jalali, Bahram

2014-01-01

Frequency domain fluorescence lifetime imaging is a powerful technique that enables the observation of subtle changes in the molecular environment of a fluorescent probe. This technique works by measuring the phase delay between the optical emission and excitation of fluorophores as a function of modulation frequency. However, high-resolution measurements are time consuming, as the excitation modulation frequency must be swept, and faster low-resolution measurements at a single frequency are prone to large errors. Here, we present a low cost optical system for applications in real-time confocal lifetime imaging, which measures the phase vs. frequency spectrum without sweeping. Deemed Lifetime Imaging using Frequency-multiplexed Excitation (LIFE), this technique uses a digitally-synthesized radio frequency comb to drive an acousto-optic deflector, operated in a cat’s-eye configuration, to produce a single laser excitation beam modulated at multiple beat frequencies. We demonstrate simultaneous fluorescence lifetime measurements at 10 frequencies over a bandwidth of 48 MHz, enabling high speed frequency domain lifetime analysis of single- and multi-component sample mixtures. PMID:25574449

Measurements of defect structures by positron annihilation lifetime spectroscopy of the tellurite glass TeO2-P2O5-ZnO-LiNbO3 doped with ions of rare earth elements: Er3+, Nd3+ and Gd3+

NASA Astrophysics Data System (ADS)

Golis, E.; Yousef, El. S.; Reben, M.; Kotynia, K.; Filipecki, J.

2015-12-01

The objective of the study was the structural analysis of the TeO2-P2O5-ZnO-LiNbO3 tellurite glasses doped with ions of the rare-earth elements: Er3+, Nd3+ and Gd3+ based on the PALS (Positron Annihilation Lifetime Spectroscopy) method of measuring positron lifetimes. Values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects, such as vacancies, mono-vacancies, dislocations or pores, the sizes of which range from a few angstroms to a few dozen nanometres. Experimental positron lifetime spectrum revealed existence of two positron lifetime components τ1 and τ2. Their interpretation was based on two-state positron trapping model where the physical parameters are the annihilation velocity and positron trapping rate.

Fiscal Impact of Smoking Cessation in Thailand: A Government Perspective Cost-Benefit Analysis.

PubMed

Connolly, Mark P; Kotsopoulos, Nikolaos; Suthipinijtham, Pichaya; Rungruanghiranya, Suthat

2018-04-01

We evaluate the broader public economic consequences of investments in smoking cessation that change lifetime productivity, which can influence future government tax revenue and social transfer costs and health care spending. The analysis applies a government perspective framework for assessing the intergenerational relationships between morbidity and mortality and lifetime tax revenue and social transfers received. Applying smoking prevalence in Thailand, a cohort model was developed for smoker and former smokers to estimate impact on lifetime direct taxes and tobacco taxes paid. Age-specific earnings for males and wage appropriate tax rates were applied to estimate net taxes for smokers and former smokers. Introducing smoking cessation leads to lifetime public economic benefits of THB13 998 to THB43 356 per person depending on the age of introducing smoking cessation. Factoring in the costs of smoking cessation therapy, an average return on investment of 1.35 was obtained indicating fiscal surplus generated for government from the combined effect of increased tax revenues and of averting smoking-attributable health care costs.

Lifetime laser damage performance of β -Ga2O3 for high power applications

NASA Astrophysics Data System (ADS)

Yoo, Jae-Hyuck; Rafique, Subrina; Lange, Andrew; Zhao, Hongping; Elhadj, Selim

2018-03-01

Gallium oxide (Ga2O3) is an emerging wide bandgap semiconductor with potential applications in power electronics and high power optical systems where gallium nitride and silicon carbide have already demonstrated unique advantages compared to gallium arsenide and silicon-based devices. Establishing the stability and breakdown conditions of these next-generation materials is critical to assessing their potential performance in devices subjected to large electric fields. Here, using systematic laser damage performance tests, we establish that β-Ga2O3 has the highest lifetime optical damage performance of any conductive material measured to date, above 10 J/cm2 (1.4 GW/cm2). This has direct implications for its use as an active component in high power laser systems and may give insight into its utility for high-power switching applications. Both heteroepitaxial and bulk β-Ga2O3 samples were benchmarked against a heteroepitaxial gallium nitride sample, revealing an order of magnitude higher optical lifetime damage threshold for β-Ga2O3. Photoluminescence and Raman spectroscopy results suggest that the exceptional damage performance of β-Ga2O3 is due to lower absorptive defect concentrations and reduced epitaxial stress.

Cost utility of maintenance treatment of recurrent depression with sertraline versus episodic treatment with dothiepin.

PubMed

Hatziandreu, E J; Brown, R E; Revicki, D A; Turner, R; Martindale, J; Levine, S; Siegel, J E

1994-03-01

The objective of this study was to model, for patients at risk of recurrent depression, the cost-utility of maintenance therapy with sertraline compared with treatment of acute episodes with dothiepin ('episodic treatment'). Using clinical decision analysis techniques, a Markov state-transition model was constructed to estimate the lifetime costs and quality-adjusted life-years (QALYs) of the 2 therapeutic strategies. The model follows 2 cohorts of 35-year-old women at high risk for recurrent depression over their lifetimes. Model construction and relevant data (probabilities) for performing the analysis were based on existing clinical knowledge. Two physician panels were used to obtain estimates of recurrence probabilities not available in the literature, health utilities, and resource consumption. Costs were obtained from published sources. The baseline analysis showed that it costs 2172 British pounds sterling ($US3692, 1991 currency) to save an additional QALY with sertraline maintenance treatment. Sensitivity analysis showed that the incremental cost-utility ratio ranged from 557 British pounds sterling to 5260 British pounds sterling per QALY. Overall, the resulting ratios are considered to be well within the range of cost-utility ratios that support the adoption and appropriate utilisation of a technology. Based on the study assumptions, long term maintenance treatment with sertraline appears to be clinically and economically justified choice for patients at high risk of recurrent depression.

High-Performance and Traditional Multicrystalline Silicon: Comparing Gettering Responses and Lifetime-Limiting Defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castellanos, Sergio; Ekstrom, Kai E.; Autruffe, Antoine

2016-05-01

In recent years, high-performance multicrystalline silicon (HPMC-Si) has emerged as an attractive alternative to traditional ingot-based multicrystalline silicon (mc-Si), with a similar cost structure but improved cell performance. Herein, we evaluate the gettering response of traditional mc-Si and HPMC-Si. Microanalytical techniques demonstrate that HPMC-Si and mc-Si share similar lifetime-limiting defect types but have different relative concentrations and distributions. HPMC-Si shows a substantial lifetime improvement after P-gettering compared with mc-Si, chiefly because of lower area fraction of dislocation-rich clusters. In both materials, the dislocation clusters and grain boundaries were associated with relatively higher interstitial iron point-defect concentrations after diffusion, which ismore » suggestive of dissolving metal-impurity precipitates. The relatively fewer dislocation clusters in HPMC-Si are shown to exhibit similar characteristics to those found in mc-Si. Given similar governing principles, a proxy to determine relative recombination activity of dislocation clusters developed for mc-Si is successfully transferred to HPMC-Si.« less

Antithrombotic Protein Filter Composed of Hybrid Tissue-Fabric Material has a Long Lifetime.

PubMed

Inoue, Yusuke; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Kaneko, Akiko; Woo, Taeseong; Kobayashi, Shingo; Shibuya, Tomokazu; Tanaka, Masaru; Kosukegawa, Hiroyuki; Saito, Itsuro; Isoyama, Takashi; Abe, Yusuke; Yambe, Tomoyuki; Someya, Takao; Sekino, Masaki

2017-05-01

There are recent reports of hybrid tissue-fabric materials with good performance-high biocompatibility and high mechanical strength. In this study, we demonstrate the capability of a hybrid material as a long-term filter for blood proteins. Polyester fabrics were implanted into rats to fabricate hybrid tissue-fabric material sheets. The hybrid materials comprised biological tissue grown on the fabric. The materials were extracted from the rat's body, approximately 100 days post-implantation. The tissues were decellularized to prevent immunological rejection. An antithrombogenicity test was performed by dropping blood onto the hybrid material surface. The hybrid material showed lesser blood coagulation than polysulfone and cellulose. Blood plasma was filtered using the hybrid material to evaluate the protein removal percentage and the lifetime of the hybrid material in vitro. The hybrid material showed a comparable performance to conventional filters for protein removal. Moreover, the hybrid material could work as a protein filter for 1 month, which is six times the lifetime of polysulfone.

Measurement of the D(s)+ lifetime.

PubMed

Link, J M; Yager, P M; Anjos, J C; Bediaga, I; Castromonte, C; Machado, A A; Magnin, J; Massafferi, A; de Miranda, J M; Pepe, I M; Polycarpo, E; dos Reis, A C; Carrillo, S; Casimiro, E; Cuautle, E; Sánchez-Hernández, A; Uribe, C; Vázquez, F; Agostino, L; Cinquini, L; Cumalat, J P; O'Reilly, B; Segoni, I; Stenson, K; Butler, J N; Cheung, H W K; Chiodini, G; Gaines, I; Garbincius, P H; Garren, L A; Gottschalk, E; Kasper, P H; Kreymer, A E; Kutschke, R; Wang, M; Benussi, L; Bertani, M; Bianco, S; Fabbri, F L; Pacetti, S; Zallo, A; Reyes, M; Cawlfield, C; Kim, D Y; Rahimi, A; Wiss, J; Gardner, R; Kryemadhi, A; Chung, Y S; Kang, J S; Ko, B R; Kwak, J W; Lee, K B; Cho, K; Park, H; Alimonti, G; Barberis, S; Boschini, M; Cerutti, A; D'Angelo, P; DiCorato, M; Dini, P; Edera, L; Erba, S; Inzani, P; Leveraro, F; Malvezzi, S; Menasce, D; Mezzadri, M; Milazzo, L; Moroni, L; Pedrini, D; Pontoglio, C; Prelz, F; Rovere, M; Sala, S; Davenport, T F; Arena, V; Boca, G; Bonomi, G; Gianini, G; Liguori, G; Pegna, D Lopes; Merlo, M M; Pantea, D; Ratti, S P; Riccardi, C; Vitulo, P; Göbel, C; Hernandez, H; Lopez, A M; Mendez, H; Paris, A; Quinones, J; Ramirez, J E; Zhang, Y; Wilson, J R; Handler, T; Mitchell, R; Engh, D; Hosack, M; Johns, W E; Luiggi, E; Moore, J E; Nehring, M; Sheldon, P D; Vaandering, E W; Webster, M; Sheaff, M

2005-07-29

A high statistics measurement of the D(s)+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis of the two decay modes, D(s)+ --> phi(1020)pi+ and D(s)+ -->K*(892)0K+, used for the measurement. The measured lifetime is 507.4 +/- 5.5(stat) +/- 5.1(syst) fs using 8961 +/- 105 D(s)+ --> phi(1020)pi+ and 4680 +/- 90 D(s)+ --> K*(892)0K+ decays. This is a significant improvement over the present world average.

Potential for adult-based epidemiological studies to characterize overall cancer risks associated with a lifetime of CT scans.

PubMed

Shuryak, Igor; Lubin, Jay H; Brenner, David J

2014-06-01

Recent epidemiological studies have suggested that radiation exposure from pediatric CT scanning is associated with small excess cancer risks. However, the majority of CT scans are performed on adults, and most radiation-induced cancers appear during middle or old age, in the same age range as background cancers. Consequently, a logical next step is to investigate the effects of CT scanning in adulthood on lifetime cancer risks by conducting adult-based, appropriately designed epidemiological studies. Here we estimate the sample size required for such studies to detect CT-associated risks. This was achieved by incorporating different age-, sex-, time- and cancer type-dependent models of radiation carcinogenesis into an in silico simulation of a population-based cohort study. This approach simulated individual histories of chest and abdominal CT exposures, deaths and cancer diagnoses. The resultant sample sizes suggest that epidemiological studies of realistically sized cohorts can detect excess lifetime cancer risks from adult CT exposures. For example, retrospective analysis of CT exposure and cancer incidence data from a population-based cohort of 0.4 to 1.3 million (depending on the carcinogenic model) CT-exposed UK adults, aged 25-65 in 1980 and followed until 2015, provides 80% power for detecting cancer risks from chest and abdominal CT scans.

Effect of Grain Boundaries on the Performance of Thin-Film-Based Polycrystalline Silicon Solar Cells: A Numerical Modeling

NASA Astrophysics Data System (ADS)

Chhetri, Nikita; Chatterjee, Somenath

2018-01-01

Solar cells/photovoltaic, a renewable energy source, is appraised to be the most effective alternative to the conventional electrical energy generator. A cost-effective alternative of crystalline wafer-based solar cell is thin-film polycrystalline-based solar cell. This paper reports the numerical analysis of dependency of the solar cell parameters (i.e., efficiency, fill factor, open-circuit voltage and short-circuit current density) on grain size for thin-film-based polycrystalline silicon (Si) solar cells. A minority carrier lifetime model is proposed to do a correlation between the grains, grain boundaries and lifetime for thin-film-based polycrystalline Si solar cells in MATLAB environment. As observed, the increment in the grain size diameter results in increase in minority carrier lifetime in polycrystalline Si thin film. A non-equivalent series resistance double-diode model is used to find the dark as well as light (AM1.5) current-voltage (I-V) characteristics for thin-film-based polycrystalline Si solar cells. To optimize the effectiveness of the proposed model, a successive approximation method is used and the corresponding fitting parameters are obtained. The model is validated with the experimentally obtained results reported elsewhere. The experimentally reported solar cell parameters can be found using the proposed model described here.

Voltage- and current-activated metal-insulator transition in VO2-based electrical switches: a lifetime operation analysis.

PubMed

Crunteanu, Aurelian; Givernaud, Julien; Leroy, Jonathan; Mardivirin, David; Champeaux, Corinne; Orlianges, Jean-Christophe; Catherinot, Alain; Blondy, Pierre

2010-12-01

Vanadium dioxide is an intensively studied material that undergoes a temperature-induced metal-insulator phase transition accompanied by a large change in electrical resistivity. Electrical switches based on this material show promising properties in terms of speed and broadband operation. The exploration of the failure behavior and reliability of such devices is very important in view of their integration in practical electronic circuits. We performed systematic lifetime investigations of two-terminal switches based on the electrical activation of the metal-insulator transition in VO 2 thin films. The devices were integrated in coplanar microwave waveguides (CPWs) in series configuration. We detected the evolution of a 10 GHz microwave signal transmitted through the CPW, modulated by the activation of the VO 2 switches in both voltage- and current-controlled modes. We demonstrated enhanced lifetime operation of current-controlled VO 2 -based switching (more than 260 million cycles without failure) compared with the voltage-activated mode (breakdown at around 16 million activation cycles). The evolution of the electrical self-oscillations of a VO 2 -based switch induced in the current-operated mode is a subtle indicator of the material properties modification and can be used to monitor its behavior under various external stresses in sensor applications.

Extending the application of DSAM to atypical stopping media

NASA Astrophysics Data System (ADS)

Das, S.; Samanta, S.; Bhattacharjee, R.; Raut, R.; Ghugre, S. S.; Sinha, A. K.; Garg, U.; Chakrabarti, R.; Mukhopadhyay, S.; Dhal, A.; Raju, M. Kumar; Madhavan, N.; Muralithar, S.; Singh, R. P.; Suryanarayana, K.; Rao, P. V. Madhusudhana; Palit, R.; Saha, S.; Sethi, J.

2017-01-01

A methodology that manifolds the possibilities of level lifetime measurements using the Doppler Shift Attenuation Method (DSAM), and extends its application beyond the conventional thin-target-on-thick-elemental-backing setups, is presented. This has been achieved primarily through application of the TRIM code to simulate the stopping of the recoils in the target and the backing media. Using the TRIM code, primarily adopted in the domain of materials research, in the context of lifetime analysis require rendition of the simulation results into a representation that appropriately incorporates the nuances of nuclear reaction along with the associated kinematics, besides the transformation from an energy-coordinate representation to a velocity-direction profile as required for lifetime analysis. The present development makes it possible to practice DSAM in atypical experimental scenarios such as those using molecular or multi-layered target and/or backing as the stopping medium. These aberrant cases, that were beyond representation in the customary Doppler shape analysis can, in the light of the present work, be conveniently used in the DSAM based investigations. The new approach has been validated through re-examination of known lifetimes measured both in the conventional as well as in the deviant setups.

The effect of 17-4PH stainless steel on the lifetime of a Pennzane lubricated Microwave Limb Sounder Antenna Actuator Assembly ball screw for the AURA spacecraft

NASA Astrophysics Data System (ADS)

Jones, William R., Jr.; Jansen, Mark J.; Chen, Gun-Shing; Lam, Jonathan; Balzer, Mark; Lo, John; Anderson, Mark; Schepis, Joseph P.

2005-07-01

During ground based life testing of a Microwave Limb Sounder (MLS) Antenna Actuator Assembly (AAA) ball-screw assembly, lubricant darkening and loss were noted when approximately 10% of required lifetime was completed. The MLS-AAA ball screw and nut are made from 17-4 PH steel, the nut has 440C stainless steel balls, and the assembly is lubricated with a Pennzane formulation containing a three weight percent lead naphthenate additive. Life tests were done in dry nitrogen at 50°C. To investigate the MLS-AAA life test anomaly, Spiral Orbit Tribometer (SOT) accelerated tests were performed. SOT results indicated greatly reduced relative lifetimes of Pennzane formulations in contact with 17-4 PH steel compared to 440C stainless steel. Also, dry nitrogen tests yielded longer relative lifetimes than comparable ultrahigh vacuum tests. Generally, oxidized Pennzane formulations yielded shorter lifetimes than non-oxidized lubricant. This study emphasizes surface chemistry effects on the lubricated lifetime of moving mechanical assemblies.

Relationship between the Fluorescence Lifetime of Chlorophyll 'a' and Primary Productivity within the Mississippi River Plume and Adjacent Shelf Region

NASA Technical Reports Server (NTRS)

Hall, Callie; Miller, Richard L.; Fernandez, Salvador M.; McKee, Brent A.

2000-01-01

In situ measurements of chlorophyll fluorescence intensity have been widely used to estimate phytoplankton biomass. However, because the fluorescence quantum yield of chlorophyll a in vivo can be highly variable, measurements of chlorophyll fluorescence intensity cannot be directly correlated with phytoplankton biomass and do not provide information on the physiological state of the phytoplankton under study. Conversely, lifetime-based measurements of chlorophyll fluorescence provide a framework in which photosynthetic rates of phytoplankton can be analyzed according to phytoplankton physiology. Along with the measurement of primary production and ambient nutrient concentrations within the Mississippi River plume in the northern Gulf of Mexico, phytoplankton fluorescence lifetimes were measured using a Fluorescence Lifetime Phytoplankton Analyzer (developed under a NASA Small Business Innovative Research contract to Ciencia, Inc.). Variability of fluorescence lifetimes within the plume can be used as a background from which to interpret variations in the maximum quantum yield of photochemistry. The extent to which nutrient and effluent loading in this dynamic coastal area affect the photosynthetic performance of phytoplankton will be presented as a function of phytoplankton fluorescence lifetimes.

The Effect of 17-4 PH Stainless Steel on the Lifetime of a Pennzane(Trademark) Lubricated Microwave Limb Sounder Antenna Actuator Assembly Ball Screw for the AURA Spacecraft

NASA Technical Reports Server (NTRS)

Jones, William R., Jr.; Jansen, Mark J.; Chen, Gun-Shing; Lam, Jonathan; Balzer, Mark; Anderson, Mark; Lo, John; Schepis, Joseph P.

2005-01-01

During ground based life testing of a Microwave Limb Sounder (MLS) Antenna Actuator Assembly (AAA) ball-screw assembly, lubricant darkening and loss were noted when approximately 10 percent of required lifetime was completed. The MLS-AAA ball screw and nut are made from 17-4 PH steel, the nut has 440C stainless steel balls, and the assembly is lubricated with a Pennzane formulation containing a three weight percent lead naphthenate additive. Life tests were done in dry nitrogen at 50 C. To investigate the MLS-AAA life test anomaly, Spiral Orbit Tribometer (SOT) accelerated tests were performed. SOT results indicated greatly reduced relative lifetimes of Pennzane formulations in contact with 17-4 PH steel compared to 440C stainless steel. Also, dry nitrogen tests yielded longer relative lifetimes than comparable ultrahigh vacuum tests. Generally, oxidized Pennzane formulations yielded shorter lifetimes than non-oxidized lubricant. This study emphasizes surface chemistry effects on the lubricated lifetime of moving mechanical assemblies.

System statistical reliability model and analysis

NASA Technical Reports Server (NTRS)

Lekach, V. S.; Rood, H.

1973-01-01

A digital computer code was developed to simulate the time-dependent behavior of the 5-kwe reactor thermoelectric system. The code was used to determine lifetime sensitivity coefficients for a number of system design parameters, such as thermoelectric module efficiency and degradation rate, radiator absorptivity and emissivity, fuel element barrier defect constant, beginning-of-life reactivity, etc. A probability distribution (mean and standard deviation) was estimated for each of these design parameters. Then, error analysis was used to obtain a probability distribution for the system lifetime (mean = 7.7 years, standard deviation = 1.1 years). From this, the probability that the system will achieve the design goal of 5 years lifetime is 0.993. This value represents an estimate of the degradation reliability of the system.

The Tribological Properties of Several Silahydrocarbons for Use in Space Mechanisms

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.; Jansen, M. J.; Gschwender, L. J.; Snyder, C. E., Jr.; Sharma, S. K.; Predmore, R. E.; Dube, M. J.

2001-01-01

Silahydrocarbons are members of a relatively new class of liquid lubricants with great potential for use in space mechanisms. They are unimolecular species consisting of silicon, carbon, and hydrogen. They possess unique wear, viscosity, and volatility properties while retaining the ability to solubilize conventional additives. The tribological properties of several members of this class, including tri, tetra- and penta-compounds, are presented. These properties include: viscosity-temperature (ASTM D446), viscosity-pressure coefficient, vapor pressure, volatility, lubricant lifetimes, traction, reciprocating and four ball wear rates and bearing performance. Lubricant lifetimes were determined using a vacuum ball bearing simulator, the spiral orbit tribometer (SOT). Wear was measured using a Cameron Plint reciprocating tribometer and wear rates with a vacuum four ball tribometer. Conventional viscometry was used for viscosity-temperature measurements and a Knudsen cell for vapor pressure. Vacuum Thermogravimetric Analysis (TGA) was also used for volatility measurements. Pressure viscosity coefficients (a values) were estimated from EHL (elastohydrodynamic lubrication) film thickness measurements. Traction coefficients were measured with a twin disk traction rig. Bearing tests were performed in a vacuum bearing test facility. These properties are compared to existing state-of-the-art space lubricants.

Alcohol Consumption in Movies and Adolescent Binge Drinking in 6 European Countries

PubMed Central

Sargent, James D.; Poelen, Evelien A. P.; Scholte, Ron; Florek, Ewa; Sweeting, Helen; Hunt, Kate; Karlsdottir, Solveig; Jonsson, Stefan Hrafn; Mathis, Federica; Faggiano, Fabrizio; Morgenstern, Matthis

2012-01-01

OBJECTIVE: The goal of this study was to investigate whether the association between exposure to images of alcohol use in movies and binge drinking among adolescents is independent of cultural context. METHODS: A cross-sectional survey study in 6 European countries (Germany, Iceland, Italy, Netherlands, Poland, and Scotland) was conducted. A total of 16 551 pupils from 114 public schools with a mean (± SD) age of 13.4 (± 1.18) years participated. By using previously validated methods, exposure to alcohol use in movies was estimated from the 250 top-grossing movies of each country (years 2004−2009). Lifetime binge drinking was the main outcome measure. RESULTS: Overall, 27% of the sample had consumed >5 drinks on at least 1 occasion in their life. After controlling for age, gender, family affluence, school performance, television screen time, sensation seeking and rebelliousness, and frequency of drinking of peers, parents, and siblings, the adjusted β-coefficient for lifetime binge drinking in the entire sample was 0.12 (95% confidence interval: 0.10−0.14; P < .001). The crude relationship between movie alcohol use exposure and lifetime binge drinking was significant in all countries; after covariate adjustment, the relationship was still significant in 5 of 6 countries. A sensitivity analysis revealed that the association is content specific, as there was no significant association between lifetime binge drinking and exposure to smoking in movies. CONCLUSIONS: The link between alcohol use in movies and adolescent binge drinking was robust and seems relatively unaffected by cultural contexts. PMID:22392174

Correlates of partner and family violence among older Canadians: a life-course approach

PubMed Central

Miszkurka, M.; Steensma, C.; Phillips, S. P.

2016-01-01

Abstract Introduction: Knowledge about individual and interpersonal correlates of violence in Canadian seniors is limited. This study identifies correlates of current and past violence by intimate partner and family member(s) in community-dwelling Canadian seniors, while accounting for childhood adverse circumstances. Methods: We performed logistic regression analysis of baseline data from a longitudinal study of community-dwelling individuals aged 65 to 74 years and living in Kingston (Ontario) and Saint-Hyacinthe (Quebec). Domestic violence was assessed using the Hurt-Insult-Threaten-Scream (HITS) screening tool. Odds ratios (ORs) are reported with 95% confidence intervals (CIs). Results: Current violence of a psychological nature was reported by 18% of the sample. Women were at greater risk of current and lifetime violence perpetrated by a family member (current violence: adjusted OR  =  1.83; 95% CI: 1.02–3.30) as well as experiencing violence from their intimate partner in their lifetime than were men (adjusted OR  =  2.48; 95% CI: 1.40–4.37). Risk factors have accumulated over the life course that were found to be consistently associated with both current and lifetime violence included having witnessed violence at home in childhood (lifetime violence by family member: adjusted OR  =  9.46; 95% CI: 5.11–17.52), as well as poor quality of relationships with intimate partners, family and friends. Conclusion: Our research documents the ongoing impact of early adversity on subsequent partner and family violence in Canada. Findings identify some preventable factors associated with current psychological violence and past violence among community-dwelling Canadian seniors. PMID:26959723

Fluorescence Lifetime Imaging Unravels C. trachomatis Metabolism and Its Crosstalk with the Host Cell

PubMed Central

Szaszák, Márta; Steven, Philipp; Shima, Kensuke; Orzekowsky-Schröder, Regina; Hüttmann, Gereon; König, Inke R.; Solbach, Werner; Rupp, Jan

2011-01-01

Chlamydia trachomatis is an obligate intracellular bacterium that alternates between two metabolically different developmental forms. We performed fluorescence lifetime imaging (FLIM) of the metabolic coenzymes, reduced nicotinamide adenine dinucleotides [NAD(P)H], by two-photon microscopy for separate analysis of host and pathogen metabolism during intracellular chlamydial infections. NAD(P)H autofluorescence was detected inside the chlamydial inclusion and showed enhanced signal intensity on the inclusion membrane as demonstrated by the co-localization with the 14-3-3β host cell protein. An increase of the fluorescence lifetime of protein-bound NAD(P)H [τ2-NAD(P)H] inside the chlamydial inclusion strongly correlated with enhanced metabolic activity of chlamydial reticulate bodies during the mid-phase of infection. Inhibition of host cell metabolism that resulted in aberrant intracellular chlamydial inclusion morphology completely abrogated the τ2-NAD(P)H increase inside the chlamydial inclusion. τ2-NAD(P)H also decreased inside chlamydial inclusions when the cells were treated with IFNγ reflecting the reduced metabolism of persistent chlamydiae. Furthermore, a significant increase in τ2-NAD(P)H and a decrease in the relative amount of free NAD(P)H inside the host cell nucleus indicated cellular starvation during intracellular chlamydial infection. Using FLIM analysis by two-photon microscopy we could visualize for the first time metabolic pathogen-host interactions during intracellular Chlamydia trachomatis infections with high spatial and temporal resolution in living cells. Our findings suggest that intracellular chlamydial metabolism is directly linked to cellular NAD(P)H signaling pathways that are involved in host cell survival and longevity. PMID:21779161

Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, Mechanical Fatigue, Creep and Thermal Fatigue Effects

NASA Technical Reports Server (NTRS)

Bast, Callie Corinne Scheidt

1994-01-01

This thesis presents the on-going development of methodology for a probabilistic material strength degradation model. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes four effects that typically reduce lifetime strength: high temperature, mechanical fatigue, creep, and thermal fatigue. Statistical analysis was conducted on experimental Inconel 718 data obtained from the open literature. This analysis provided regression parameters for use as the model's empirical material constants, thus calibrating the model specifically for Inconel 718. Model calibration was carried out for four variables, namely, high temperature, mechanical fatigue, creep, and thermal fatigue. Methodology to estimate standard deviations of these material constants for input into the probabilistic material strength model was developed. Using the current version of PROMISS, entitled PROMISS93, a sensitivity study for the combined effects of mechanical fatigue, creep, and thermal fatigue was performed. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing a combination of mechanical fatigue and high temperature effects by model to the combination by experiment were conducted. Thus, for Inconel 718, the basic model assumption of independence between effects was evaluated. Results from this limited verification study strongly supported this assumption.

MEMS based shock pulse detection sensor for improved rotary Stirling cooler end of life prediction

NASA Astrophysics Data System (ADS)

Hübner, M.; Münzberg, M.

2018-05-01

The widespread use of rotary Stirling coolers in high performance thermal imagers used for critical 24/7 surveillance tasks justifies any effort to significantly enhance the reliability and predictable uptime of those coolers. Typically the lifetime of the whole imaging device is limited due to continuous wear and finally failure of the rotary compressor of the Stirling cooler, especially due to failure of the comprised bearings. MTTF based lifetime predictions, even based on refined MTTF models taking operational scenario dependent scaling factors into account, still lack in precision to forecast accurately the end of life (EOL) of individual coolers. Consequently preventive maintenance of individual coolers to avoid failures of the main sensor in critical operational scenarios are very costly or even useless. We have developed an integrated test method based on `Micro Electromechanical Systems', so called MEMS sensors, which significantly improves the cooler EOL prediction. The recently commercially available MEMS acceleration sensors have mechanical resonance frequencies up to 50 kHz. They are able to detect solid borne shock pulses in the cooler structure, originating from e.g. metal on metal impacts driven by periodical forces acting on moving inner parts of the rotary compressor within wear dependent slack and play. The impact driven transient shock pulse analyses uses only the high frequency signal <10kHz and differs therefore from the commonly used broadband low frequencies vibrational analysis of reciprocating machines. It offers a direct indicator of the individual state of wear. The predictive cooler lifetime model based on the shock pulse analysis is presented and results are discussed.

Susceptibility to Childhood Pneumonia: A Genome-Wide Analysis.

PubMed

Hayden, Lystra P; Cho, Michael H; McDonald, Merry-Lynn N; Crapo, James D; Beaty, Terri H; Silverman, Edwin K; Hersh, Craig P

2017-01-01

Previous studies have indicated that in adult smokers, a history of childhood pneumonia is associated with reduced lung function and chronic obstructive pulmonary disease. There have been few previous investigations using genome-wide association studies to investigate genetic predisposition to pneumonia. This study aims to identify the genetic variants associated with the development of pneumonia during childhood and over the course of the lifetime. Study subjects included current and former smokers with and without chronic obstructive pulmonary disease participating in the COPDGene Study. Pneumonia was defined by subject self-report, with childhood pneumonia categorized as having the first episode at <16 years. Genome-wide association studies for childhood pneumonia (843 cases, 9,091 control subjects) and lifetime pneumonia (3,766 cases, 5,659 control subjects) were performed separately in non-Hispanic whites and African Americans. Non-Hispanic white and African American populations were combined in the meta-analysis. Top genetic variants from childhood pneumonia were assessed in network analysis. No single-nucleotide polymorphisms reached genome-wide significance, although we identified potential regions of interest. In the childhood pneumonia analysis, this included variants in NGR1 (P = 6.3 × 10 -8 ), PAK6 (P = 3.3 × 10 -7 ), and near MATN1 (P = 2.8 × 10 -7 ). In the lifetime pneumonia analysis, this included variants in LOC339862 (P = 8.7 × 10 -7 ), RAPGEF2 (P = 8.4 × 10 -7 ), PHACTR1 (P = 6.1 × 10 -7 ), near PRR27 (P = 4.3 × 10 -7 ), and near MCPH1 (P = 2.7 × 10 -7 ). Network analysis of the genes associated with childhood pneumonia included top networks related to development, blood vessel morphogenesis, muscle contraction, WNT signaling, DNA damage, apoptosis, inflammation, and immune response (P ≤ 0.05). We have identified genes potentially associated with the risk of pneumonia. Further research will be required to confirm these associations and to determine biological mechanisms. NCT00608764.

Lifetime indirect cost of childhood overweight and obesity: A decision analytic model.

PubMed

Sonntag, Diana; Ali, Shehzad; De Bock, Freia

2016-01-01

To estimate the indirect lifetime cost of childhood overweight and obesity for Germany. The lifetime cohort model consisted of two parts: (a) Model I used data from the German Interview and Examination Survey for Children on prevalence of BMI categories during childhood to evaluate BMI trajectories before the age of 18; and (b) Model II estimated lifetime excess indirect cost based on the history of childhood BMI. Indirect costs were defined as the opportunity cost of lost productivity due to mortality and morbidity and were identified through a systematic literature review. Our analysis showed that the majority of children with overweight and obesity remained in the same BMI category during their adult life, resulting in significant indirect lifetime costs. We estimated that overweight and obesity during childhood resulted in an excess lifetime cost per person of €4,209 (men) and €2,445 (women). For the current prevalent German population, the excess lifetime cost was €145 billion. Our study showed that childhood obesity results in significant economic burden on the society. Therefore, cost-effective strategies targeted at reducing the prevalence of obesity during the early years of life can significantly reduce both healthcare and nonhealthcare costs over the lifetime. © 2015 The Obesity Society.

Systematics in position annihilation lifetime analysis of high T c superconducting transitions

NASA Astrophysics Data System (ADS)

Howell, R. H.; Radousky, H. B.; Wachs, A. L.; Fluss, M. J.; Turchi, P. E. A.; Jean, Y. C.; Sundar, C. S.; Chu, C. W.; Peng, J. L.; Folkerts, T. J.; Shelton, R. N.; Hinks, D. G.

1989-12-01

Values of the positron lifetime have previously been observed to change with temperature below T c in high T c superconducting oxides. We report new measurements on Ba .6K .4BiO 3 and Nd 1.85Ce .15CuO 4.

Experiments and analysis of a compact electrothermal thruster

NASA Technical Reports Server (NTRS)

Asmussen, Jes; Whitehair, Stan

1988-01-01

The description and experimental performance of a compact microwave electrothermal thruster (MET) are presented. This thruster uses a coaxial applicator to couple microwave power into a high pressure discharge. Unlike earlier experiments, it uses no fused quartz in the discharge chamber or the nozzle. This allows high temperatures in the discharge chamber without quartz erosion and melting, thereby improving thruster performance and lifetime. The thruster design is compact, enhancing its potential as a space engine. Experimental tests using nitrogen and helium propellants with input powers levels of 200 W to 1.5 kW are presented. Experimental results, which produce energy efficiencies of 20 to 60 percent and specific impulse of 250 to 450 sec, compare favorably to previous experimental MET performance.

Community Energy Storage Thermal Analysis and Management: Cooperative Research and Development Final Report, CRADA Number CRD-11-445

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Kandler A.

The goal of this project is to create thermal solutions and models for community energy storage devices using both purpose-designed batteries and EV or PHEV batteries. Modeling will be employed to identify major factors of a device's lifetime and performance. Simultaneously, several devices will be characterized to determine their electrical and thermal performance under controlled conditions. After the factors are identified, a variety of thermal design approaches will be evaluated to improve the performance of energy storage devices. Upon completion of this project, recommendations for community energy storage device enclosures, thermal management systems, and/or battery sourcing will be made. NREL'smore » interest is in both new and aged batteries.« less

A total internal reflection-fluorescence correlation spectroscopy setup with pulsed diode laser excitation

NASA Astrophysics Data System (ADS)

Weger, Lukas; Hoffmann-Jacobsen, Kerstin

2017-09-01

Fluorescence correlation spectroscopy (FCS) measures fluctuations in a (sub-)femtoliter volume to analyze the diffusive behavior of fluorescent particles. This highly sensitive method has proven to be useful for the analysis of dynamic biological systems as well as in chemistry, physics, and material sciences. It is routinely performed with commercial fluorescence microscopes, which provide a confined observation volume by the confocal technique. The evanescent wave of total internal reflectance (TIR) is used in home-built systems to permit a surface sensitive FCS analysis. We present a combined confocal and TIR-FCS setup which uses economic low-power pulsed diode lasers for excitation. Excitation and detection are coupled to time-correlated photon counting hardware. This allows simultaneous fluorescence lifetime and FCS measurements in a surface-sensitive mode. Moreover, the setup supports fluorescence lifetime correlation spectroscopy at surfaces. The excitation can be easily switched between TIR and epi-illumination to compare the surface properties with those in liquid bulk. The capabilities of the presented setup are demonstrated by measuring the diffusion coefficients of a free dye molecule, a labeled polyethylene glycol, and a fluorescent nanoparticle in confocal as well as in TIR-FCS.

Accelerated Test Method for Corrosion Protective Coatings Project

NASA Technical Reports Server (NTRS)

Falker, John; Zeitlin, Nancy; Calle, Luz

2015-01-01

This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

Effects of service condition on rolling contact fatigue failure mechanism and lifetime of thermal spray coatings—A review

NASA Astrophysics Data System (ADS)

Cui, Huawei; Cui, Xiufang; Wang, Haidou; Xing, Zhiguo; Jin, Guo

2015-01-01

The service condition determines the Rolling Contact Fatigue(RCF) failure mechanism and lifetime under ascertain material structure integrity parameter of thermal spray coating. The available literature on the RCF testing of thermal spray coatings under various condition services is considerable; it is generally difficult to synthesize all of the result to obtain a comprehensive understanding of the parameters which has a great effect on a thermal spray coating's resistance of RCF. The effects of service conditions(lubrication states, contact stresses, revolve speed, and slip ratio) on the changing of thermal spray coatings' contact fatigue lifetime is introduced systematically. The effects of different service condition on RCF failure mechanism of thermal spray coating from the change of material structure integrity are also summarized. Moreover, In order to enhance the RCF performance, the parameter optimal design formula of service condition and material structure integrity is proposed based on the effect of service condition on thermal spray coatings' contact fatigue lifetime and RCF failure mechanism. The shortage of available literature and the forecast focus in future researches are discussed based on available research. The explicit result of RCF lifetime law and parameter optimal design formula in term of lubrication states, contact stresses, revolve speed, and slip ratio, is significant to improve the RCF performance on the engineering application.

Game theoretic approach for cooperative feature extraction in camera networks

NASA Astrophysics Data System (ADS)

Redondi, Alessandro E. C.; Baroffio, Luca; Cesana, Matteo; Tagliasacchi, Marco

2016-07-01

Visual sensor networks (VSNs) consist of several camera nodes with wireless communication capabilities that can perform visual analysis tasks such as object identification, recognition, and tracking. Often, VSN deployments result in many camera nodes with overlapping fields of view. In the past, such redundancy has been exploited in two different ways: (1) to improve the accuracy/quality of the visual analysis task by exploiting multiview information or (2) to reduce the energy consumed for performing the visual task, by applying temporal scheduling techniques among the cameras. We propose a game theoretic framework based on the Nash bargaining solution to bridge the gap between the two aforementioned approaches. The key tenet of the proposed framework is for cameras to reduce the consumed energy in the analysis process by exploiting the redundancy in the reciprocal fields of view. Experimental results in both simulated and real-life scenarios confirm that the proposed scheme is able to increase the network lifetime, with a negligible loss in terms of visual analysis accuracy.

Deployment-based lifetime optimization model for homogeneous Wireless Sensor Network under retransmission.

PubMed

Li, Ruiying; Liu, Xiaoxi; Xie, Wei; Huang, Ning

2014-12-10

Sensor-deployment-based lifetime optimization is one of the most effective methods used to prolong the lifetime of Wireless Sensor Network (WSN) by reducing the distance-sensitive energy consumption. In this paper, data retransmission, a major consumption factor that is usually neglected in the previous work, is considered. For a homogeneous WSN, monitoring a circular target area with a centered base station, a sensor deployment model based on regular hexagonal grids is analyzed. To maximize the WSN lifetime, optimization models for both uniform and non-uniform deployment schemes are proposed by constraining on coverage, connectivity and success transmission rate. Based on the data transmission analysis in a data gathering cycle, the WSN lifetime in the model can be obtained through quantifying the energy consumption at each sensor location. The results of case studies show that it is meaningful to consider data retransmission in the lifetime optimization. In particular, our investigations indicate that, with the same lifetime requirement, the number of sensors needed in a non-uniform topology is much less than that in a uniform one. Finally, compared with a random scheme, simulation results further verify the advantage of our deployment model.

Mental Disorders, Comorbidity, and Postrunaway Arrests among Homeless and Runaway Adolescents

ERIC Educational Resources Information Center

Chen, Xiaojin; Thrane, Lisa; Whitbeck, Les B.; Johnson, Kurt

2006-01-01

This study examined the associations between lifetime mental disorder, comorbidity, and self-reported postrunaway arrests among 428 (187 males, 241 females) homeless and runaway youth. The analysis examined the pattern of arrests across five lifetime mental disorders (alcohol abuse, drug abuse, conduct disorder, major depressive episode, and…

Low lifetime stress exposure is associated with reduced stimulus–response memory

PubMed Central

Goldfarb, Elizabeth V.; Shields, Grant S.; Daw, Nathaniel D.; Slavich, George M.; Phelps, Elizabeth A.

2017-01-01

Exposure to stress throughout life can cumulatively influence later health, even among young adults. The negative effects of high cumulative stress exposure are well-known, and a shift from episodic to stimulus–response memory has been proposed to underlie forms of psychopathology that are related to high lifetime stress. At the other extreme, effects of very low stress exposure are mixed, with some studies reporting that low stress leads to better outcomes, while others demonstrate that low stress is associated with diminished resilience and negative outcomes. However, the influence of very low lifetime stress exposure on episodic and stimulus–response memory is unknown. Here we use a lifetime stress assessment system (STRAIN) to assess cumulative lifetime stress exposure and measure memory performance in young adults reporting very low and moderate levels of lifetime stress exposure. Relative to moderate levels of stress, very low levels of lifetime stress were associated with reduced use and retention (24 h later) of stimulus–response (SR) associations, and a higher likelihood of using context memory. Further, computational modeling revealed that participants with low levels of stress exhibited worse expression of memory for SR associations than those with moderate stress. These results demonstrate that very low levels of stress exposure can have negative effects on cognition. PMID:28298555

Quantitative multi-color FRET measurements by Fourier lifetime excitation-emission matrix spectroscopy.

PubMed

Zhao, Ming; Huang, Run; Peng, Leilei

2012-11-19

Förster resonant energy transfer (FRET) is extensively used to probe macromolecular interactions and conformation changes. The established FRET lifetime analysis method measures the FRET process through its effect on the donor lifetime. In this paper we present a method that directly probes the time-resolved FRET signal with frequency domain Fourier lifetime excitation-emission matrix (FLEEM) measurements. FLEEM separates fluorescent signals by their different phonon energy pathways from excitation to emission. The FRET process generates a unique signal channel that is initiated by donor excitation but ends with acceptor emission. Time-resolved analysis of the FRET EEM channel allows direct measurements on the FRET process, unaffected by free fluorophores that might be present in the sample. Together with time-resolved analysis on non-FRET channels, i.e. donor and acceptor EEM channels, time resolved EEM analysis allows precise quantification of FRET in the presence of free fluorophores. The method is extended to three-color FRET processes, where quantification with traditional methods remains challenging because of the significantly increased complexity in the three-way FRET interactions. We demonstrate the time-resolved EEM analysis method with quantification of three-color FRET in incompletely hybridized triple-labeled DNA oligonucleotides. Quantitative measurements of the three-color FRET process in triple-labeled dsDNA are obtained in the presence of free single-labeled ssDNA and double-labeled dsDNA. The results establish a quantification method for studying multi-color FRET between multiple macromolecules in biochemical equilibrium.

Quantitative multi-color FRET measurements by Fourier lifetime excitation-emission matrix spectroscopy

PubMed Central

Zhao, Ming; Huang, Run; Peng, Leilei

2012-01-01

Förster resonant energy transfer (FRET) is extensively used to probe macromolecular interactions and conformation changes. The established FRET lifetime analysis method measures the FRET process through its effect on the donor lifetime. In this paper we present a method that directly probes the time-resolved FRET signal with frequency domain Fourier lifetime excitation-emission matrix (FLEEM) measurements. FLEEM separates fluorescent signals by their different phonon energy pathways from excitation to emission. The FRET process generates a unique signal channel that is initiated by donor excitation but ends with acceptor emission. Time-resolved analysis of the FRET EEM channel allows direct measurements on the FRET process, unaffected by free fluorophores that might be present in the sample. Together with time-resolved analysis on non-FRET channels, i.e. donor and acceptor EEM channels, time resolved EEM analysis allows precise quantification of FRET in the presence of free fluorophores. The method is extended to three-color FRET processes, where quantification with traditional methods remains challenging because of the significantly increased complexity in the three-way FRET interactions. We demonstrate the time-resolved EEM analysis method with quantification of three-color FRET in incompletely hybridized triple-labeled DNA oligonucleotides. Quantitative measurements of the three-color FRET process in triple-labeled dsDNA are obtained in the presence of free single-labeled ssDNA and double-labeled dsDNA. The results establish a quantification method for studying multi-color FRET between multiple macromolecules in biochemical equilibrium. PMID:23187535

Energy acceptance and on momentum aperture optimization for the Sirius project

NASA Astrophysics Data System (ADS)

Dester, P. S.; Sá, F. H.; Liu, L.

2017-07-01

A fast objective function to calculate Touschek lifetime and on momentum aperture is essential to explore the vast search space of strength of quadrupole and sextupole families in Sirius. Touschek lifetime is estimated by using the energy aperture (dynamic and physical), RF system parameters and driving terms. Non-linear induced betatron oscillations are considered to determine the energy aperture. On momentum aperture is estimated by using a chaos indicator and resonance crossing considerations. Touschek lifetime and on momentum aperture constitute the objective function, which was used in a multi-objective genetic algorithm to perform an optimization for Sirius.

Improving Lifetime of Quasi-CW Laser Diode Arrays for Pumping 2-Micron Solid State Lasers

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Singh, Upendra N.; Kavaya, Michael J.

2007-01-01

Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data on the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

Correlation between lifetime heterogeneity and kinetics heterogeneity during chlorophyll fluorescence induction in leaves: 2. Multi-frequency phase and modulation analysis evidences a loosely connected PSII pigment-protein complex.

PubMed

Moise, Nicolae; Moya, Ismaël

2004-06-28

We report the first direct decomposition of the fluorescence lifetime heterogeneity during multiphasic fluorescence induction in dark-adapted leaves by multi-frequency phase and modulation fluorometry (PMF). A very fast component, assigned to photosystem I (PSI), was found to be constant in lifetime and yield, whereas the two slow components, which are strongly affected by the closure of the reaction centers by light, were assigned to PSII. Based on a modified "reversible radical pair" kinetic model with three compartments, we showed that a loosely connected pigment complex, which is assumed to be the CP47 complex, plays a specific role with respect to the structure and function of the PSII: (i) it explains the heterogeneity of PSII fluorescence lifetime as a compartmentation of excitation energy in the antenna, (ii) it is the site of a conformational change in the first second of illumination, and (iii) it is involved in the mechanisms of nonphotochemical quenching (NPQ). On the basis of the multi-frequency PMF analysis, we reconciled two apparently antagonistic aspects of chlorophyll a fluorescence in vivo: it is heterogeneous with respect to the kinetic structure (several lifetime components) and homogeneous with respect to average quantities (quasi-linear mean tau-Phi relationship).

Long-range ballistic motion and coherent flow of long-lifetime polaritons

NASA Astrophysics Data System (ADS)

Steger, Mark; Liu, Gangqiang; Nelsen, Bryan; Gautham, Chitra; Snoke, David W.; Balili, Ryan; Pfeiffer, Loren; West, Ken

2013-12-01

Exciton polaritons can be created in semiconductor microcavities. These quasiparticles act as weakly interacting bosons with very light mass, of the order of 10-4 times the vacuum electron mass. Many experiments have shown effects which can be viewed as due to a Bose-Einstein condensate, or quasicondensate, of these particles. The lifetime of the particles in most of those experiments has been of the order of a few picoseconds, leading to significant nonequilibrium effects. By increasing the cavity quality, we have made samples with longer polariton lifetimes. With a photon lifetime on the order of 100-200 ps, polaritons in these structures can not only come closer to reaching true thermal equilibrium, a desired feature for many researchers working in this field, but they can also travel much longer distances. We observe the polaritons to ballistically travel on the order of 1 mm, and at higher densities we see transport of a coherent condensate, or quasicondensate, over comparable distances. In this paper we report a quantitative analysis of the flow of the polaritons both in a low-density, classical regime, and in the coherent regime at higher density. Our analysis gives us a measure of the intrinsic lifetime for photon decay from the microcavity and a measure of the strength of interactions of the polaritons.

The atmospheric lifetime of black carbon

NASA Astrophysics Data System (ADS)

Cape, J. N.; Coyle, M.; Dumitrean, P.

2012-11-01

Black carbon (BC) in the atmosphere contributes to the human health effects of particulate matter and contributes to radiative forcing of climate. The lifetime of BC, particularly the smaller particle sizes (PM2.5) which can be transported over long distances, is therefore an important factor in determining the range of such effects, and the spatial footprint of emission controls. Theory and models suggest that the typical lifetime of BC is around one week. The frequency distributions of measurements of a range of hydrocarbons at a remote rural site in southern Scotland (Auchencorth Moss) between 2007 and 2010 have been used to quantify the relationship between atmospheric lifetime and the geometric standard deviation of observed concentration. The analysis relies on an assumed common major emission source for hydrocarbons and BC, namely diesel-engined vehicles. The logarithm of the standard deviation of the log-transformed concentration data is linearly related to hydrocarbon lifetime, and the same statistic for BC can be used to assess the lifetime of BC relative to the hydrocarbons. Annual average data show BC lifetimes in the range 4-12 days, for an assumed OH concentration of 7 × 105 cm-3. At this site there is little difference in BC lifetime between winter and summer, despite a 3-fold difference in relative hydrocarbon lifetimes. This observation confirms the role of wet deposition as an important removal process for BC, as there is no difference in precipitation between winter and summer at this site. BC lifetime was significantly greater in 2010, which had 23% less rainfall than the preceding 3 years.

Electron Generation of Leptons and Hadrons with Conjugate α-QUANTIZED Lifetimes and Masses

NASA Astrophysics Data System (ADS)

Mac Gregor, Malcolm H.

In elementary particle theories the fine structure constant α = e2/ℏc serves as the coupling constant for lepton interactions (QED), but is assumed to play no role in hadron interactions (QCD). However, experiments have long indicated an α spacing in the lifetimes of the long-lived threshold-state hadrons, and they also suggest an α-related mass structure. Lifetimes and masses are conjugate quantum mechanical variables, so the α-dependence of these two variables is a mutual property. The relevance of α to hadron interactions is an experimental question, independent of theory. In the present paper we first make a detailed analysis of the experimental lifetime data. This analysis demonstrates that out of 156 particles with well-determined lifetimes τ, the 120 short excited-state lifetimes τ<10-21 sec have a continuum of values, but the 36 long threshold-state lifetimes τ>10-21 sec occur in α-spaced groups that cleanly sort out the s, c, b quark flavors. These 36 metastable lifetimes also exhibit a factor-of-3 c-to-b "flavor structure" and a pervasive factor-of-2 "hyperfine structure." We then invoke the conjugate relationship between lifetimes and masses to trace out an α-defined set of mass quanta that tie together leptons and hadrons. Mass generation occurs via an initial "α-leap" from an electron pair to a "platform state" M, and then subsequent excitations by a dominant quantum X. The low-mass "MX octet" of particles — μ, p, τ, π, η, η‧, K, ϕ — is reproduced to an average accuracy of 0.4%, with no adjustable parameters except a small binding energy for hadronic pairs. Without the inclusion of lepton masses, the spectrum of hadron masses is difficult to understand. These conjugate α-quantized results reinforce the reality of the spin 1/2 u, d, s, c, b quarks, and they also lead to the identification of a closely-related set of spinless mass quanta for the pseudoscalar mesons.

Executive Functioning in Men with Schizophrenia and Substance Use Disorders. Influence of Lifetime Suicide Attempts

PubMed Central

Capella, Maria del Mar; Prat, Gemma; Forero, Diego A.; López-Vera, Silvia; Navarro, José Francisco

2017-01-01

Background Lifetime suicide attempts in patients with comorbidity between psychotic disorders and Substance Use Disorder (SUD), known as dual diagnosis, was associated with a worse clinical and cognitive state, poor prognosis and premature death. However, to date no previous study has examined the cognitive performance of these patients considering as independent the presence or absence of lifetime suicide attempts. Methods We explore executive functioning differences between suicide attempters and non-attempters in dual schizophrenia (DS) patients and the possible related factors for both executive performance and current suicide risk. Fifty DS male patients in remission of SUD and clinically stables, 24 with and 26 without lifetime suicide attempts, were evaluated. We considered Z scores for all neuropsychological tests and a composite summary score for both premorbid IQ and executive functioning. Results DS patients showed low performance in set-shifting, planning and problem solving tasks. Those with suicide attempts presented lower composite summary scores, together with worse problem solving skills and decision-making, compared with non-attempters. However, after controlling for alcohol dependence, only differences in decision-making remained. Executive functioning was related to the premorbid intelligence quotient, and several clinical variables (duration, severity, months of abstinence and relapses of SUD, global functioning and negative symptoms). A relationship between current suicide risk, and first-degree relatives with SUD, insight and positive symptoms was also found. Conclusions Our results suggest that problem solving and, especially, decision-making tasks might be sensitive to cognitive impairment of DS patients related to presence of lifetime suicide attempts. The assessment of these executive functions and cognitive remediation therapy when necessary could be beneficial for the effectiveness of treatment in patients with DS. However, further research is needed to expand our findings and overcome some limitations of this study. PMID:28099526

Executive Functioning in Men with Schizophrenia and Substance Use Disorders. Influence of Lifetime Suicide Attempts.

PubMed

Adan, Ana; Capella, Maria Del Mar; Prat, Gemma; Forero, Diego A; López-Vera, Silvia; Navarro, José Francisco

2017-01-01

Lifetime suicide attempts in patients with comorbidity between psychotic disorders and Substance Use Disorder (SUD), known as dual diagnosis, was associated with a worse clinical and cognitive state, poor prognosis and premature death. However, to date no previous study has examined the cognitive performance of these patients considering as independent the presence or absence of lifetime suicide attempts. We explore executive functioning differences between suicide attempters and non-attempters in dual schizophrenia (DS) patients and the possible related factors for both executive performance and current suicide risk. Fifty DS male patients in remission of SUD and clinically stables, 24 with and 26 without lifetime suicide attempts, were evaluated. We considered Z scores for all neuropsychological tests and a composite summary score for both premorbid IQ and executive functioning. DS patients showed low performance in set-shifting, planning and problem solving tasks. Those with suicide attempts presented lower composite summary scores, together with worse problem solving skills and decision-making, compared with non-attempters. However, after controlling for alcohol dependence, only differences in decision-making remained. Executive functioning was related to the premorbid intelligence quotient, and several clinical variables (duration, severity, months of abstinence and relapses of SUD, global functioning and negative symptoms). A relationship between current suicide risk, and first-degree relatives with SUD, insight and positive symptoms was also found. Our results suggest that problem solving and, especially, decision-making tasks might be sensitive to cognitive impairment of DS patients related to presence of lifetime suicide attempts. The assessment of these executive functions and cognitive remediation therapy when necessary could be beneficial for the effectiveness of treatment in patients with DS. However, further research is needed to expand our findings and overcome some limitations of this study.

Gastric bypass is a cost-saving procedure: results from a comprehensive Markov model.

PubMed

Faria, Gil R; Preto, John R; Costa-Maia, José

2013-04-01

Obesity is a growing public health problem in industrialized countries and is directly and indirectly responsible for almost 10% of all health expenditures. Bariatric surgery is the best available treatment, however, associated with important economical expenditures. So, cost-effectiveness analysis of the available surgical options is paramount. We developed a Markov model for three different strategies: best medical management, gastric band, and gastric bypass. The Markov model was constructed to allow for the evaluation of the impact of several obesity-related comorbidities. The results were derived for a representative population of morbidly obese patients, and subgroup analyses were performed for patients without comorbidities, patients with diabetes mellitus, different age, and body mass index (BMI) groups. Cost-effectiveness analysis was performed accounting for lifetime costs and from a societal perspective. Gastric bypass is a dominant strategy, rendering a significant decrease in lifetime costs and increase in quality-adjusted life years (QALYs). Comparing with the best medical management, in the global population of patients with a BMI of > 35 kg/m2, gastric bypass renders 1.9 extra QALYs and saves on average 13,244€ per patient. Younger patients, patients with a BMI between 40 and 50 kg/m2, and patients without obesity-related diseases are the ones with a bigger benefit in terms of cost effectiveness. Gastric bypass surgery increases quality-adjusted survival and saves resources to health systems. As such, it can be an important process to control the ever-increasing health expenditure.

Positron annihilation lifetime study of oxide dispersion strengthened steels

NASA Astrophysics Data System (ADS)

Krsjak, V.; Szaraz, Z.; Hähner, P.

2012-09-01

A comparative positron annihilation lifetime study has been performed on various commercial ferritic and ferritic/martensitic oxide dispersion strengthened (ODS) steels. Both as-extruded and recrystallized materials were investigated. In the materials with recrystallized coarse-grained microstructures, only the positron trapping at small vacancy clusters and yttria nanofeatures was observed. Materials which had not undergone recrystallization treatment clearly showed additional positron trapping which is associated with dislocations. Dislocation densities were calculated from a two-component decomposition of the positron lifetime spectra by assuming the first component to be a superposition of the bulk controlled annihilation rate and the dislocation controlled trapping rate. The second component (which translates into lifetimes of 240-260 ps) was found to be well separated in all those ODS materials. This paper presents the potentialities and limitations of the positron annihilation lifetime spectroscopy, and discusses the results of the experimental determination of the defect concentrations and sensitivity of this technique to the material degradation due to thermally induced precipitation of chromium-rich α' phases.

Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes

PubMed Central

Fujimoto, Hiroshi; Suekane, Takashi; Imanishi, Katsuya; Yukiwaki, Satoshi; Wei, Hong; Nagayoshi, Kaori; Yahiro, Masayuki; Adachi, Chihaya

2016-01-01

We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility. PMID:27958304

Mesopore quality determines the lifetime of hierarchically structured zeolite catalysts

NASA Astrophysics Data System (ADS)

Milina, Maria; Mitchell, Sharon; Crivelli, Paolo; Cooke, David; Pérez-Ramírez, Javier

2014-05-01

Deactivation due to coking limits the lifetime of zeolite catalysts in the production of chemicals and fuels. Superior performance can be achieved through hierarchically structuring the zeolite porosity, yet no relation has been established between the mesopore architecture and the catalyst lifetime. Here we introduce a top-down demetallation strategy to locate mesopores in different regions of MFI-type crystals with identical bulk porous and acidic properties. In contrast, well-established bottom-up strategies as carbon templating and seed silanization fail to yield materials with matching characteristics. Advanced characterization tools capable of accurately discriminating the mesopore size, distribution and connectivity are applied to corroborate the concept of mesopore quality. Positron annihilation lifetime spectroscopy proves powerful to quantify the global connectivity of the intracrystalline pore network, which, as demonstrated in the conversions of methanol or of propanal to hydrocarbons, is closely linked to the lifetime of zeolite catalysts. The findings emphasize the need to aptly tailor hierarchical materials for maximal catalytic advantage.

Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Fujimoto, Hiroshi; Suekane, Takashi; Imanishi, Katsuya; Yukiwaki, Satoshi; Wei, Hong; Nagayoshi, Kaori; Yahiro, Masayuki; Adachi, Chihaya

2016-12-01

We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Lijuan; Gonder, Jeff; Burton, Evan

This study evaluates the costs and benefits associated with the use of a plug-in hybrid electric bus and determines the cost effectiveness relative to a conventional bus and a hybrid electric bus. A sensitivity sweep analysis was performed over a number of a different battery sizes, charging powers, and charging stations. The net present value was calculated for each vehicle design and provided the basis for the design evaluation. In all cases, given present day economic assumptions, the conventional bus achieved the lowest net present value while the optimal plug-in hybrid electric bus scenario reached lower lifetime costs than themore » hybrid electric bus. The study also performed parameter sensitivity analysis under low market potential assumptions and high market potential assumptions. The net present value of plug-in hybrid electric bus is close to that of conventional bus.« less

FUNDUS AUTOFLUORESCENCE LIFETIMES AND CENTRAL SEROUS CHORIORETINOPATHY.

PubMed

Dysli, Chantal; Berger, Lieselotte; Wolf, Sebastian; Zinkernagel, Martin S

2017-11-01

To quantify retinal fluorescence lifetimes in patients with central serous chorioretinopathy (CSC) and to identify disease specific lifetime characteristics over the course of disease. Forty-seven participants were included in this study. Patients with central serous chorioretinopathy were imaged with fundus photography, fundus autofluorescence, optical coherence tomography, and fluorescence lifetime imaging ophthalmoscopy (FLIO) and compared with age-matched controls. Retinal autofluorescence was excited using a 473-nm blue laser light and emitted fluorescence light was detected in 2 distinct wavelengths channels (498-560 nm and 560-720 nm). Clinical features, mean retinal autofluorescence lifetimes, autofluorescence intensity, and corresponding optical coherence tomography (OCT) images were further analyzed. Thirty-five central serous chorioretinopathy patients with a mean visual acuity of 78 ETDRS letters (range, 50-90; mean Snellen equivalent: 20/32) and 12 age-matched controls were included. In the acute stage of central serous chorioretinopathy, retinal fluorescence lifetimes were shortened by 15% and 17% in the respective wavelength channels. Multiple linear regression analysis showed that fluorescence lifetimes were significantly influenced by the disease duration (P < 0.001) and accumulation of photoreceptor outer segments (P = 0.03) but independent of the presence or absence of subretinal fluid. Prolonged central macular autofluorescence lifetimes, particularly in eyes with retinal pigment epithelial atrophy, were associated with poor visual acuity. This study establishes that autofluorescence lifetime changes occurring in central serous chorioretinopathy exhibit explicit patterns which can be used to estimate perturbations of the outer retinal layers with a high degree of statistical significance.

The fiscal consequences of ADHD in Germany: a quantitative analysis based on differences in educational attainment and lifetime earnings.

PubMed

Kotsopoulos, Nikolaos; Connolly, Mark P; Sobanski, Esther; Postma, Maarten J

2013-03-01

To estimate the long-term fiscal consequences of attention deficit hyperactivity disorder (ADHD) on the German government and social insurance system based on differences in educational attainment and the resulting differences in lifetime earnings compared with non-ADHD cohorts. Differences in educational attainment between ADHD and non-ADHD cohorts were linked to education-specific earnings data. Direct and indirect tax rates and social insurance contributions were linked to differences in lifetime, education-specific earnings to derive lost tax revenue in Germany associated with ADHD. For ADHD and non-ADHD cohorts we derived the age-specific discounted net taxes paid by deducting lifetime transfers from lifetime gross taxes paid. The lifetime net tax revenue for a non-ADHD individual was approximately EUR 80,000 higher compared to an untreated ADHD individual. The fiscal burden of untreated ADHD, based on a cohort of n=31,844 born in 2010, was estimated at EUR 2.5 billion in net tax revenue losses compared with an equally-sized non-ADHD cohort. ADHD interventions providing a small improvement in educational attainment resulted in fiscal benefits from increases in lifetime tax gains. ADHD results in long-term financial loss due to lower education attainment and lifetime reduced earnings and resulting lifetime taxes and social contributions paid. Investments in ADHD interventions allowing more children to achieve their educational potential may offer fiscal benefits generating a positive rate of return.

A CMOS Time-Resolved Fluorescence Lifetime Analysis Micro-System

PubMed Central

Rae, Bruce R.; Muir, Keith R.; Gong, Zheng; McKendry, Jonathan; Girkin, John M.; Gu, Erdan; Renshaw, David; Dawson, Martin D.; Henderson, Robert K.

2009-01-01

We describe a CMOS-based micro-system for time-resolved fluorescence lifetime analysis. It comprises a 16 × 4 array of single-photon avalanche diodes (SPADs) fabricated in 0.35 μm high-voltage CMOS technology with in-pixel time-gated photon counting circuitry and a second device incorporating an 8 × 8 AlInGaN blue micro-pixellated light-emitting diode (micro-LED) array bump-bonded to an equivalent array of LED drivers realized in a standard low-voltage 0.35 μm CMOS technology, capable of producing excitation pulses with a width of 777 ps (FWHM). This system replaces instrumentation based on lasers, photomultiplier tubes, bulk optics and discrete electronics with a PC-based micro-system. Demonstrator lifetime measurements of colloidal quantum dot and Rhodamine samples are presented. PMID:22291564

Effects of ligand binding on the conformation and internal dynamics in specific regions of porcine pancreatic phospholipase A2 with tryptophan as a probe: a study combining time-resolved fluorescence spectroscopy and site-directed mutagenesis (same as p. 100)

NASA Astrophysics Data System (ADS)

Kuipers, Oscar; Vincent, Michel; Brochon, Jean-Claude; Verheij, Bert; de Haas, Gerard; Gallay, Jacques

1990-05-01

Exploration of the effect of ligand-protein interactions on conformational substates and internal dynamics in different regions of phospholipase A2 from porcine pancreas (PLA2), was performed by combining site-directed mutagenesis and time-resolved fluorescence measurements. The single tryptophan residue (Trp-3) in the wild type protein was replaced by a phenylalanine residue, whereafter Trp was substituted either for leucine-31 ,located in the calcium binding loop, or for phenylalanine-94, located at the "back side" of the enzyme, in a-helix E (Dijkstra et al., J. Mol. Biol., 147, 97-123, 1981). Analyses by the Maximum Entropy Method (MIEM) of the total fluorescence intensity decays, provide in each case a distribution of separate lifetime classes, which can be interpreted as reflecting the existence of discrete conformational substates in slow exchange with respect to the time-scale of the decay kinetics. The fluorescence decay of the W94 mutant is dominated by an extremely short excited state lifetime of ~60 ps, probably arising from the presence of two proximate disulfide bridges. Time-resolved fluorescence anisotropy studies show that the Trp residue near the NH2 terminus (Trp-3) undergoes a more limited rotational motion than the Trp-3 1 located in the calcium binding loop. The widest angular rotation is observed at position 94, in a-helix E. Calcium binding displays the strongest influence on the lifetime distribution of Trp-31: a major local conformation corresponding to a lifetime class with a barycenter value of ~5.5 ns and contributing to ~50% of the decay is selected. The conformations giving rise to the short lifetimes ((tau)1 and (tau)2 lifetime classes) become less important. The contribution of the third lifetime class (c3) stays at a constant value of 30%. In the presence of calcium, the amplitude of motion is wider than without the ion. There is virtually no effect of calcium binding on the lifetime distribution of the Trp residue at the 3 or the 94 position. Binding of the monomeric substrate analog n-dodecylphosphocholine (C12PN) in the presence of calcium hardly affects neither the Trp-3 excited state population distribution, nor its rotational dynamics. The binding of C12PN monomers to the W31 mutant further increases the contribution of the t4lifetime class at the expense of c2. A more restricted rotation of the Trp-31 residue is also induced. The binding of the micellar substrate analog n-hexadecylphosphocholine (C16PN) in the presence of calcium is very efficient in modifying the lifetime distribution of Trp-3. Essentially, one major broad lifetime population (centered at ~2.6 ns) is revealed by MEM analysis of the total intensity decay. The internal motion is slowed down and the angle of rotation is much smaller in this conformation. Neither the excited state lifetime distribution of Trp-31 nor its dynamics are affected by micelle binding relative to monomer binding. In conclusion, by placing a single Tip-residue at strategic positions along the peptide chain of PLA2, relevant to the binding of biological ligands, an excellent model system for the study of selective perturbations of conformational substates and internal dynamics is provided.

Effects of ligand binding on the conformation and internal dynamics in specific regions of porcine pancreatic phospholipase A2 with tryptophan as a probe: a study combinging time-resolved fluorescence spectroscopy and site-directed mutagenesis (same as p. 628)

NASA Astrophysics Data System (ADS)

Kuipers, Oscar; Vincent, Michel; Brochon, Jean-Claude; Verheij, Bert; de Haas, Gerard; Gallay, Jacques

1990-05-01

Exploration of the effect of ligand-protein interactions on conformational substates and internal dynamics in different regions of phospholipase A2 from porcine pancreas (PLA2), was performed by combining site-directed mutagenesis and time-resolved fluorescence measurements. The single tryptophan residue (Trp-3) in the wild type protein was replaced by a phenylalanine residue, whereafter Tip was substituted either for leucine-3 1 ,located in the calcium binding ioop, or for phenylalanine-94, located at the "back side" of the enzyme, in a-helix E (Dijkstra et al., J. Mol. Biol., 147, 97-123, 1981). Analyses by the Maximum Entropy Method (MEM) of the total fluorescence intensity decays, provide in each case a distribution of separate lifetime classes, which can be interpreted as reflecting the existence of discrete conformational substates in slow exchange with respect to the time-scale of the decay kinetics. The fluorescence decay of the W94 mutant is. dominated by an extremely short excited state lifetime of ~60 ps, probably arising from the presence of two proximate disulfide bridges. Time-resolved fluorescence anisotropy studies show that the Trp residue near the NH2 terminus (Trp-3) undergoes a more limited rotational motion than the Trp-3 1 located in the calcium binding loop. The widest angular rotation is observed at position 94, in a-helix E. Calcium binding displays the strongest influence on the lifetime distribution of Trp-3 1: a major local conformation corresponding to a lifetime class with a barycenter value of -5.5 ns and contributing to ~50% of the decay is selected. The conformations giving rise to the short lifetimes (τ1 and τ2 lifetime classes) become less important. The contribution of the third lifetime class (c3) stays at a constant value of 30%. In the presence of calcium, the amplitude of motion is wider than without the ion. There is virtually no effect of calcium binding on the lifetime distribution of the Trp residue at the 3 or the 94 position. Binding of the monomeric substrate analog n-dodecylphosphocholine (C12PN) in the presence of calcium hardly affects neither the Trp-3 excited state population distribution, nor its rotational dynamics. The binding of C12PN monomers to the W31 mutant further increases the contribution of the τ4 lifetime class at the expense of c2. A more restricted rotation of the Trp-3 1 residue is also induced. The binding of the micellar substrate analog n-hexadecylphosphocholine (C16PN) in the presence of calcium is very efficient in modifying the lifetime distribution of Trp-3. Essentially, one major broad lifetime population (centered at ~2.6 ns) is revealed by MEM analysis of the total intensity decay. The internal motion is slowed down and the angle of rotation is much smaller in this conformation. Neither the excited state lifetime distribution of Trp-31 nor its dynamics are affected by micelle binding relative to monomer binding. In conclusion, by placing a single Tip-residue at strategic positions along the peptide chain of PLA2, relevant to the binding of biological ligands, an excellent model system for the study of selective perturbations of conformational substates and internal dynamics is provided.

Characteristic Lifetime Of A Polarized Feature In The V=0, J=1-0 Sio Maser VY Canis Majoris

NASA Astrophysics Data System (ADS)

Rislow, Benjamin; McIntosh, G. C.

2008-05-01

A time series cross correlation analysis has been developed for calculating the characteristic lifetime of linearly polarized features in the spectrum of silicon monoxide masers. Our observations of VY CMa in the v=0, J=1→0; transition from June 2003 to March 2006 revealed a highly linearly polarized feature at Vlsr=18.5 km s-1. Applying the cross correlation to this feature gave a characteristic lifetime of 2800 days. This time is much longer than the v=1, J=2→1; transition's lifetime of 645 days and indicates that the two transitions occur under different physical conditions. This research was supported by the University of Minnesota and the University of Minnesota, Morris.

Risk analysis for worker exposure to benzene

NASA Astrophysics Data System (ADS)

Hallenbeck, William H.; Flowers, Roxanne E.

1992-05-01

Cancer risk factors (characterized by route, dose, dose rate per kilogram, fraction of lifetime exposed, species, and sex) were derived for workers exposed to benzene via inhalation or ingestion. Exposure at the current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) and at leaking underground storage tank (LUST) sites were evaluated. At the current PEL of 1 ppm, the theoretical lifetime excess risk of cancer from benzene inhalation is ten per 1000. The theoretical lifetime excess risk for worker inhalation exposure at LUST sites ranged from 10 to 40 per 1000. These results indicate that personal protection should be required. The theoretical lifetime excess risk due to soil ingestion is five to seven orders of magnitude less than the inhalation risks.

Application of the differential decay-curve method to γ-γ fast-timing lifetime measurements

NASA Astrophysics Data System (ADS)

Petkov, P.; Régis, J.-M.; Dewald, A.; Kisyov, S.

2016-10-01

A new procedure for the analysis of delayed-coincidence lifetime experiments focused on the Fast-timing case is proposed following the approach of the Differential decay-curve method. Examples of application of the procedure on experimental data reveal its reliability for lifetimes even in the sub-nanosecond range. The procedure is expected to improve both precision/reliability and treatment of systematic errors and scarce data as well as to provide an option for cross-check with the results obtained by means of other analyzing methods.

Indoor Air Quality in High Performance Schools

EPA Pesticide Factsheets

High performance schools are facilities that improve the learning environment while saving energy, resources, and money. The key is understanding the lifetime value of high performance schools and effectively managing priorities, time, and budget.

Indoor Air Quality in High Performance Schools

EPA Pesticide Factsheets

2017-02-14

High performance schools are facilities that improve the learning environment while saving energy, resources, and money. The key is understanding the lifetime value of high performance schools and effectively managing priorities, time, and budget.

Lifetime testing UV LEDs for use in the LISA charge management system

NASA Astrophysics Data System (ADS)

Hollington, D.; Baird, J. T.; Sumner, T. J.; Wass, P. J.

2017-10-01

As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the laser interferometer space antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent pulsed fast discharge test spanning 21 days and a pulsed continuous discharge test spanning 507 days. Two types of UV LED have demonstrated lifetimes equivalent to over 25 years of realistic mission usage with one type providing a baseline for LISA and the other offering a backup solution.

Determining the Environmental Benefits of Ultra High Performance Concrete as a Bridge Construction Material

NASA Astrophysics Data System (ADS)

Lande Larsen, Ingrid; Granseth Aasbakken, Ida; O'Born, Reyn; Vertes, Katalin; Terje Thorstensen, Rein

2017-10-01

Ultra High Performance Concrete (UHPC) is a material that is attracting attention in the construction industry due to the high mechanical strength and durability, leading to structures having low maintenance requirements. The production of UHPC, however, has generally higher environmental impact than normal strength concrete due to the increased demand of cement required in the concrete mix. What is still not sufficiently investigated, is if the longer lifetime, slimmer construction and lower maintenance requirements lead to a net environmental benefit compared to standard concrete bridge design. This study utilizes life cycle assessment (LCA) to determine the lifetime impacts of two comparable highway crossing footbridges spanning 40 meters, designed respectively with UHPC and normal strength concrete. The results of the study show that UHPC is an effective material for reducing lifetime emissions from construction and maintenance of long lasting infrastructure, as the UHPC design outperforms the normal strength concrete bridge in most impact categories.

Age is no barrier: predictors of academic success in older learners

NASA Astrophysics Data System (ADS)

Imlach, Abbie-Rose; Ward, David D.; Stuart, Kimberley E.; Summers, Mathew J.; Valenzuela, Michael J.; King, Anna E.; Saunders, Nichole L.; Summers, Jeffrey; Srikanth, Velandai K.; Robinson, Andrew; Vickers, James C.

2017-11-01

Although predictors of academic success have been identified in young adults, such predictors are unlikely to translate directly to an older student population, where such information is scarce. The current study aimed to examine cognitive, psychosocial, lifetime, and genetic predictors of university-level academic performance in older adults (50-79 years old). Participants were mostly female (71%) and had a greater than high school education level (M = 14.06 years, SD = 2.76), on average. Two multiple linear regression analyses were conducted. The first examined all potential predictors of grade point average (GPA) in the subset of participants who had volunteered samples for genetic analysis (N = 181). Significant predictors of GPA were then re-examined in a second multiple linear regression using the full sample (N = 329). Our data show that the cognitive domains of episodic memory and language processing, in conjunction with midlife engagement in cognitively stimulating activities, have a role in predicting academic performance as measured by GPA in the first year of study. In contrast, it was determined that age, IQ, gender, working memory, psychosocial factors, and common brain gene polymorphisms linked to brain function, plasticity and degeneration (APOE, BDNF, COMT, KIBRA, SERT) did not influence academic performance. These findings demonstrate that ageing does not impede academic achievement, and that discrete cognitive skills as well as lifetime engagement in cognitively stimulating activities can promote academic success in older adults.

Process Research On Polycrystalline Silicon Material (PROPSM). [flat plate solar array project

NASA Technical Reports Server (NTRS)

Culik, J. S.

1983-01-01

The performance-limiting mechanisms in large-grain (greater than 1 to 2 mm in diameter) polycrystalline silicon solar cells were investigated by fabricating a matrix of 4 sq cm solar cells of various thickness from 10 cm x 10 cm polycrystalline silicon wafers of several bulk resistivities. Analysis of the illuminated I-V characteristics of these cells suggests that bulk recombination is the dominant factor limiting the short-circuit current. The average open-circuit voltage of the polycrystalline solar cells is 30 to 70 mV lower than that of co-processed single-crystal cells; the fill-factor is comparable. Both open-circuit voltage and fill-factor of the polycrystalline cells have substantial scatter that is not related to either thickness or resistivity. This implies that these characteristics are sensitive to an additional mechanism that is probably spatial in nature. A damage-gettering heat-treatment improved the minority-carrier diffusion length in low lifetime polycrystalline silicon, however, extended high temperature heat-treatment degraded the lifetime.

Lifetime Extension of the Gas Discharge Detectors with Plasma Etching of Silicon Deposits in 80%CF4 + 20%CO2

NASA Astrophysics Data System (ADS)

Gavrilov, G. E.; Vakhtel, V. M.; Maysuzenko, D. A.; Tavtorkina, T. A.; Fetisov, A. A.; Shvetsova, N. Yu.

2017-12-01

A method of elimination of silicon compounds from the anode wire of an aged proportional counter is presented. The aging of a counter with a 70%Ar + 30%CO2 and a 60%Ar + 30%CO2 + 10%CF4 working mixture was stimulated by a 90Sr β source. To accelerate the process of aging, the gas mixture flow to the counter was supplied through a pipe with RTV coated wall. As a result, the amplitude of the signal decreased 70% already at accumulated charge of Q = 0.03 C/cm. The etching of the silicon compounds on the wire surface with an 80%CF4 + 20%CO2 gas mixture discharge led to full recovery of the operating characteristics of detector and an increase in the lifetime. A scanning electron microscopy and X-ray spectroscopy analysis of the recovered wire surface were performed. In accordance with the results, a good quality of wire cleaning from SiO2 compounds was obtained.

Thallous chalcogenide (Tl 6I 4Se) for radiation detection at X-ray and γ-ray energies

NASA Astrophysics Data System (ADS)

Liu, Zhifu; Peters, John A.; Wessels, Bruce W.; Johnsen, Simon; Kanatzidis, Mercouri G.

2011-12-01

The optical and charge transport properties of the thallous chalcogenide compound Tl6I4Se were characterized. The semiconductor crystals are grown by the modified Bridgman method. We have measured the refractive index, and absorption coefficient of the compound ranging from 300 to 1500 nm by analysis of the UV-vis-near IR transmission and reflection spectra. The band gap is 1.8 eV. For the evaluation of detector performance, the mobility-lifetime products for both the electron and hole carriers were measured. Tl6I4Se has mobility-lifetime products of 7.1×10-3 and 5.9×10-4 cm2/V for electron and hole carriers, respectively, which are comparable to those of Cd0.9Zn0.1Te. The γ-ray spectrum for a Tl6I4Se detector was measured. Its response to the 122 keV of 57Co source is comparable to that of Cd0.9Zn0.1Te.

Risk factors, lifetime risk, and age at onset of breast cancer.

PubMed

Fraser, G E; Shavlik, D

1997-08-01

We evaluated the relationship between exposure variables and both lifetime risk and mean age at diagnosis of breast cancer in subjects from the Adventist Health Study who developed breast cancer before the age of 91 years. Multiple decrement life-table analysis was used. This study provided data from 20,341 women followed for 6 years. In the total population, 30-year-old women with a parental history of any cancer or a maternal history of breast cancer had, respectively, 72% (P < 0.002) and 98% (P < 0.03) higher lifetime risks of breast cancer. Thirty-year-old women who had their first delivery after age 24 years or body mass indices above the 50th percentile had, respectively, 53% (P < 0.007) or 57% (P = 0.01) greater lifetime risk of breast cancer. Women who exercised infrequently had a 27% higher life-time risk (P = 0.09) and an age at diagnosis of breast cancer 6.6 years younger (P < 0.005) than other women. Standard risk factors account for substantial increases in lifetime risk of breast cancer and may be associated with differences in age at diagnosis.

Corrosion Preventive Compounds Lifetime Testing

NASA Technical Reports Server (NTRS)

Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.

2007-01-01

Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

Corrosion Preventive Compounds Lifetime Testing

NASA Technical Reports Server (NTRS)

Hale, Stephanie M.; Kammerer, Catherine C.

2007-01-01

Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: HD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

Cost-effectiveness of sensor-augmented pump therapy versus standard insulin pump therapy in patients with type 1 diabetes in Denmark.

PubMed

Roze, S; de Portu, S; Smith-Palmer, J; Delbaere, A; Valentine, W; Ridderstråle, M

2017-06-01

The use of continuous subcutaneous insulin infusion (CSII) in type 1 diabetes (T1D) has increased in recent years. Sensor-augmented pump therapy (SAP) with low glucose suspend (LGS) (allowing temporary suspension of insulin delivery if blood glucose level falls below a pre-defined threshold level) provides additional benefits over CSII alone, but is associated with higher acquisition costs. Therefore, a cost-effectiveness analysis of SAP+LGS versus CSII in patients with T1D was performed. Analyses were performed using the CORE Diabetes Model in two different patient cohorts in Denmark, one with hyperglycemia at baseline and one with increased risk for hypoglycemic events. Clinical input data were sourced from published literature. The analysis was performed over a lifetime time horizon from a societal perspective. Future costs and clinical outcomes were discounted at 3% per annum. In patients who were hyperglycemic at baseline the use of SAP+LGS versus CSII resulted in improved quality-adjusted life expectancy (12.44 versus 10.99 quality-adjusted life years [QALYs]) but higher mean lifetime costs (DKK 2,027,316 versus DKK 1,801,293) leading to an incremental cost-effectiveness ratio (ICER) of DKK 156,082 per QALY gained. For patients at increased risk for hypoglycemic events the ICER for SAP+LGS versus CSII was DKK 89,868 per QALY gained. The ICER for SAP+LGS versus CSII falls below commonly cited willingness-to-pay thresholds. Therefore, in Denmark, the use of SAP+LGS is likely to be considered cost-effective relative to CSII for patients with T1D who are either hyperglycemic, despite CSII use, or who experience frequent severe hypoglycemic events. Copyright © 2017 Elsevier B.V. All rights reserved.

The Effectiveness of a Constant Time Delay Procedure on Teaching Lifetime Sport Skills to Adolescents with Severe to Profound Intellectual Disabilities.

ERIC Educational Resources Information Center

Zhang, Jiabei; And Others

1995-01-01

A constant time delay (CTD) procedure was used to teach four adolescents with severe/profound intellectual disabilities to perform bowling, throwing, and putting. Results indicated that the adolescents could be effectively taught gross motor lifetime sport skills with the CTD procedure and that verbal description plus physical assistance could be…

Time-dependent breakdown of fiber networks: Uncertainty of lifetime

NASA Astrophysics Data System (ADS)

Mattsson, Amanda; Uesaka, Tetsu

2017-05-01

Materials often fail when subjected to stresses over a prolonged period. The time to failure, also called the lifetime, is known to exhibit large variability of many materials, particularly brittle and quasibrittle materials. For example, a coefficient of variation reaches 100% or even more. Its distribution shape is highly skewed toward zero lifetime, implying a large number of premature failures. This behavior contrasts with that of normal strength, which shows a variation of only 4%-10% and a nearly bell-shaped distribution. The fundamental cause of this large and unique variability of lifetime is not well understood because of the complex interplay between stochastic processes taking place on the molecular level and the hierarchical and disordered structure of the material. We have constructed fiber network models, both regular and random, as a paradigm for general material structures. With such networks, we have performed Monte Carlo simulations of creep failure to establish explicit relationships among fiber characteristics, network structures, system size, and lifetime distribution. We found that fiber characteristics have large, sometimes dominating, influences on the lifetime variability of a network. Among the factors investigated, geometrical disorders of the network were found to be essential to explain the large variability and highly skewed shape of the lifetime distribution. With increasing network size, the distribution asymptotically approaches a double-exponential form. The implication of this result is that, so-called "infant mortality," which is often predicted by the Weibull approximation of the lifetime distribution, may not exist for a large system.

A simple procedure for γ- γ lifetime measurements using multi-element fast-timing arrays

NASA Astrophysics Data System (ADS)

Régis, J.-M.; Dannhoff, M.; Jolie, J.

2018-07-01

The lifetimes of nuclear excited states are important observables in nuclear physics. Their precise measurement is of key importance for developing and testing nuclear models as they are directly linked with the quantum nature of the nuclear system. The γ- γ timing technique represents a direct lifetime determination by means of time-difference measurements between the γ rays which directly feed and decay from a nuclear excited state. Using arrays of very-fast scintillator detectors, picosecond-sensitive time-difference measurements can be performed. We propose to construct a symmetric energy-energy-time cube as is usually done to perform γ- γ coincidence analyses and lifetime determination with high-resolution germanium detectors. By construction, a symmetric mean time-walk characteristics is obtained, that can be precisely determined and used as a single time correction for all the data independently of the detectors. We present the results of timing characteristics measurements of an array with six LaBr3(Ce) detectors, as obtained using a 152Eu point γ-ray source. Compared with a single detector pair, the time resolution of the symmetrised time-difference spectra of the array is nearly unaffected.

Guanidinium: A Route to Enhanced Carrier Lifetime and Open-Circuit Voltage in Hybrid Perovskite Solar Cells.

PubMed

De Marco, Nicholas; Zhou, Huanping; Chen, Qi; Sun, Pengyu; Liu, Zonghao; Meng, Lei; Yao, En-Ping; Liu, Yongsheng; Schiffer, Andy; Yang, Yang

2016-02-10

Hybrid perovskites have shown astonishing power conversion efficiencies owed to their remarkable absorber characteristics including long carrier lifetimes, and a relatively substantial defect tolerance for solution-processed polycrystalline films. However, nonradiative charge carrier recombination at grain boundaries limits open circuit voltages and consequent performance improvements of perovskite solar cells. Here we address such recombination pathways and demonstrate a passivation effect through guanidinium-based additives to achieve extraordinarily enhanced carrier lifetimes and higher obtainable open circuit voltages. Time-resolved photoluminescence measurements yield carrier lifetimes in guanidinium-based films an order of magnitude greater than pure-methylammonium counterparts, giving rise to higher device open circuit voltages and power conversion efficiencies exceeding 17%. A reduction in defect activation energy of over 30% calculated via admittance spectroscopy and confocal fluorescence intensity mapping indicates successful passivation of recombination/trap centers at grain boundaries. We speculate that guanidinium ions serve to suppress formation of iodide vacancies and passivate under-coordinated iodine species at grain boundaries and within the bulk through their hydrogen bonding capability. These results present a simple method for suppressing nonradiative carrier loss in hybrid perovskites to further improve performances toward highly efficient solar cells.

Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

NASA Technical Reports Server (NTRS)

Munday, Jeremy

2016-01-01

Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

Comparison of lifetime-based methods for 2D phosphor thermometry in high-temperature environment

NASA Astrophysics Data System (ADS)

Peng, Di; Liu, Yingzheng; Zhao, Xiaofeng; Kim, Kyung Chun

2016-09-01

This paper discusses the currently available techniques for 2D phosphor thermometry, and compares the performance of two lifetime-based methods: high-speed imaging and the dual-gate. High-speed imaging resolves luminescent decay with a fast frame rate, and has become a popular method for phosphor thermometry in recent years. But it has disadvantages such as high equipment cost and long data processing time, and it would fail at sufficiently high temperature due to a low signal-to-noise ratio and short lifetime. The dual-gate method only requires two images on the decay curve and therefore greatly reduces cost in hardware and processing time. A dual-gate method for phosphor thermometry has been developed and compared with the high-speed imaging method through both calibration and a jet impingement experiment. Measurement uncertainty has been evaluated for a temperature range of 473-833 K. The effects of several key factors on uncertainty have been discussed, including the luminescent signal level, the decay lifetime and temperature sensitivity. The results show that both methods are valid for 2D temperature sensing within the given range. The high-speed imaging method shows less uncertainty at low temperatures where the signal level and the lifetime are both sufficient, but its performance is degraded at higher temperatures due to a rapidly reduced signal and lifetime. For T  >  750 K, the dual-gate method outperforms the high-speed imaging method thanks to its superiority in signal-to-noise ratio and temperature sensitivity. The dual-gate method has great potential for applications in high-temperature environments where the high-speed imaging method is not applicable.

Enzymatic Transition States, Transition-State Analogs, Dynamics, Thermodynamics, and Lifetimes

PubMed Central

Schramm, Vern L.

2017-01-01

Experimental analysis of enzymatic transition-state structures uses kinetic isotope effects (KIEs) to report on bonding and geometry differences between reactants and the transition state. Computational correlation of experimental values with chemical models permits three-dimensional geometric and electrostatic assignment of transition states formed at enzymatic catalytic sites. The combination of experimental and computational access to transition-state information permits (a) the design of transition-state analogs as powerful enzymatic inhibitors, (b) exploration of protein features linked to transition-state structure, (c) analysis of ensemble atomic motions involved in achieving the transition state, (d) transition-state lifetimes, and (e) separation of ground-state (Michaelis complexes) from transition-state effects. Transition-state analogs with picomolar dissociation constants have been achieved for several enzymatic targets. Transition states of closely related isozymes indicate that the protein’s dynamic architecture is linked to transition-state structure. Fast dynamic motions in catalytic sites are linked to transition-state generation. Enzymatic transition states have lifetimes of femtoseconds, the lifetime of bond vibrations. Binding isotope effects (BIEs) reveal relative reactant and transition-state analog binding distortion for comparison with actual transition states. PMID:21675920

Renal Mass Biopsy to Guide Treatment Decisions for Small Incidental Renal Tumors: A Cost-effectiveness Analysis1

PubMed Central

Gervais, Debra A.; Hartman, Rebecca I.; Harisinghani, Mukesh G.; Feldman, Adam S.; Mueller, Peter R.; Gazelle, G. Scott

2010-01-01

Purpose: To evaluate the effectiveness, cost, and cost-effectiveness of using renal mass biopsy to guide treatment decisions for small incidentally detected renal tumors. Materials and Methods: A decision-analytic Markov model was developed to estimate life expectancy and lifetime costs for patients with small (≤4-cm) renal tumors. Two strategies were compared: renal mass biopsy to triage patients to surgery or imaging surveillance and empiric nephron-sparing surgery. The model incorporated biopsy performance, the probability of track seeding with malignant cells, the prevalence and growth of benign and malignant tumors, treatment effectiveness and costs, and patient outcomes. An incremental cost-effectiveness analysis was performed to identify strategy preference under a willingness-to-pay threshold of $75 000 per quality-adjusted life-year (QALY). Effects of changes in key parameters on strategy preference were evaluated in sensitivity analysis. Results: Under base-case assumptions, the biopsy strategy yielded a minimally greater quality-adjusted life expectancy (4 days) than did empiric surgery at a lower lifetime cost ($3466), dominating surgery from a cost-effectiveness perspective. Over the majority of parameter ranges tested in one-way sensitivity analysis, the biopsy strategy dominated surgery or was cost-effective relative to surgery based on a $75 000-per-QALY willingness-to-pay threshold. In two-way sensitivity analysis, surgery yielded greater life expectancy when the prevalence of malignancy and propensity for biopsy-negative cancers to metastasize were both higher than expected or when the sensitivity and specificity of biopsy were both lower than expected. Conclusion: The use of biopsy to guide treatment decisions for small incidentally detected renal tumors is cost-effective and can prevent unnecessary surgery in many cases. © RSNA, 2010 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10092013/-/DC1 PMID:20720070

Time-domain laser-induced fluorescence spectroscopy apparatus for clinical diagnostics

NASA Astrophysics Data System (ADS)

Fang, Qiyin; Papaioannou, Thanassis; Jo, Javier A.; Vaitha, Russel; Shastry, Kumar; Marcu, Laura

2004-01-01

We report the design and development of a compact optical fiber-based apparatus for in situ time-resolved laser-induced fluorescence spectroscopy (tr-LIFS) of biological systems. The apparatus is modular, optically robust, and compatible with the clinical environment. It incorporates a dual output imaging spectrograph, a gated multichannel plate photomultiplier (MCP-PMT), an intensified charge-coupled-device (ICCD) camera, and a fast digitizer. It can accommodate various types of light sources and optical fiber probes for selective excitation and remote light delivery/collection as required by different applications. The apparatus allows direct recording of the entire fluorescence decay with high sensitivity (nM range fluorescein dye concentration with signal-to-noise ratio of 46) and with four decades dynamic range. It is capable of resolving a broad range of fluorescence lifetimes from hundreds of picoseconds (as low as 300 ps) using the MCP-PMT coupled to the digitizer to milliseconds using the ICCD. The data acquisition and analysis process is fully automated, enabling fast recording of fluorescence intensity decay across the entire emission spectrum (0.8 s per wavelength or ˜40 s for a 200 nm wavelength range at 5 nm increments). The spectral and temporal responses of the apparatus were calibrated and its performance was validated using fluorescence lifetime standard dyes (Rhodamin B, 9-cyanoanthracene, and rose Bengal) and tissue endogenous fluorophores (elastin, collagen, nicotinamide adenine dinucleotide, and flavin adenine dinucleotide). Fluorescence decay lifetimes and emission spectra of all tested compounds measured with the current tr-LIFS apparatus were found in good agreement with the values reported in the literature. The design and performance of tr-LIFS apparatus have enabled in vivo studies of atherosclerotic plaques and brain tumors.

Recurrent suicide attempts in patients with depressive and anxiety disorders: the role of borderline personality traits.

PubMed

Stringer, Barbara; van Meijel, Berno; Eikelenboom, Merijn; Koekkoek, Bauke; Licht, Carmilla M M; Kerkhof, Ad J F M; Penninx, Brenda W J H; Beekman, Aartjan T F

2013-10-01

The presence of a comorbid borderline personality disorder (BPD) may be associated with an increase of suicidal behaviors in patients with depressive and anxiety disorders. The aim of this study is to examine the role of borderline personality traits on recurrent suicide attempts. The Netherlands Study on Depression and Anxiety included 1838 respondents with lifetime depressive and/or anxiety disorders, of whom 309 reported at least one previous suicide attempt. A univariable negative binomial regression analysis was performed to examine the association between comorbid borderline personality traits and suicide attempts. Univariable and multivariable negative binomial regression analyses were performed to identify risk factors for the number of recurrent suicide attempts in four clusters (type and severity of axis-I disorders, BPD traits, determinants of suicide attempts and socio-demographics). In the total sample the suicide attempt rate ratio increased with 33% for every unit increase in BPD traits. A lifetime diagnosis of dysthymia and comorbid BPD traits, especially the symptoms anger and fights, were independently and significantly associated with recurrent suicide attempts in the final model (n=309). The screening of personality disorders was added to the NESDA assessments at the 4-year follow-up for the first time. Therefore we were not able to examine the influence of comorbid BPD traits on suicide attempts over time. Persons with a lifetime diagnosis of dysthymia combined with borderline personality traits especially difficulties in coping with anger seemed to be at high risk for recurrent suicide attempts. For clinical practice, it is recommended to screen for comorbid borderline personality traits and to strengthen the patient's coping skills with regard to anger. © 2013 Elsevier B.V. All rights reserved.

Long-term health economic benefits of sensor-augmented pump therapy vs continuous subcutaneous insulin infusion alone in type 1 diabetes: a U.K. perspective.

PubMed

Roze, Stéphane; Smith-Palmer, Jayne; Valentine, William J; Cook, Mark; Jethwa, Manisha; de Portu, Simona; Pickup, John C

2016-01-01

Continuous subcutaneous insulin infusion (CSII) is an important treatment option for type 1 diabetes patients unable to achieve adequate glycemic control with multiple daily injections (MDI). Combining CSII with continuous glucose monitoring (CGM) in sensor-augmented pump therapy (SAP) with a low glucose-suspend (LGS) feature may further improve glycemic control and reduce the frequency of hypoglycemia. A cost-effectiveness analysis of SAP + LGS vs. CSII plus self-monitoring of blood glucose (SMBG) was performed to determine the health economic benefits of SAP + LGS in type 1 diabetes patients using CSII in the U.K. Cost-effectiveness analysis was performed using the CORE diabetes model. Treatment effects were sourced from the literature, where SAP + LGS was associated with a projected HbA1c reduction of -1.49% vs. -0.62% for CSII, and a reduced frequency of severe hypoglycemia. The time horizon was that of patient lifetimes; future costs and clinical outcomes were discounted at 3.5% and 1.5% per annum, respectively. Projected outcomes showed that SAP + LGS was associated with higher mean quality-adjusted life expectancy (17.9 vs. 14.9 quality-adjusted life years [QALYs], SAP + LGS vs. CSII), and higher life expectancy (23.8 vs. 21.9 years), but higher mean lifetime direct costs (GBP 125,559 vs. GBP 88,991), leading to an incremental cost-effectiveness ratio (ICER) of GBP 12,233 per QALY gained for SAP + LGS vs. CSII. Findings of the base-case analysis remained robust in sensitivity analyses. For UK-based type 1 diabetes patients with poor glycemic control, the use of SAP + LGS is likely to be cost-effective compared with CSII plus SMBG.

Correlation Between Optoelectronic and Positron Lifetime Properties in As-received and Plasma-treated ZnO Nanopowders

NASA Astrophysics Data System (ADS)

Peters, R. M.; Paramo, J. A.; Quarles, C. A.; Strzhemechny, Y. M.

2009-03-01

We employed photoluminescence and positron lifetime measurements on a number of commercially available ZnO nanopowders. The experiments were performed before and after processing of these samples in remote N and O/He plasma. In all the nanopowders, the average lifetime component is substantially longer than in a single-crystalline sample, consistent with the model of grains with defect-rich surface and subsurface layers. However, the sample-to-sample differences in the quality of the powders, as detected by the photoluminescence spectroscopy, obscure observation of possible size effects. Compression of the powders into pellets yields reductions of the average positron lifetimes. Plasma-induced modifications are most visible in the low-temperature photoluminescence spectra of the smallest nanocrystals, indicative of a surface-specific nature of the chosen treatment procedure.

International Space Station Major Constituent Analyzer On-Orbit Performance

NASA Technical Reports Server (NTRS)

Gardner, Ben D.; Erwin, Phillip M.; Thoresen, Souzan; Wiedemann, Rachel; Matty, Chris

2015-01-01

The Major Constituent Analyzer is a mass spectrometer based system that measures the major atmospheric constituents on the International Space Station. A number of limited-life components require periodic change-out, including the ORU 02 analyzer and the ORU 08 Verification Gas Assembly. Improvements to ion pump operation and ion source tuning have improved lifetime performance of the current ORU 02 design. The most recent ORU 02 analyzer assemblies, as well as ORU 08, have operated nominally. For ORU 02, the ion source filaments and ion pump lifetime continue to be key determinants of MCA performance and logistical support. Monitoring several key parameters provides the capacity to monitor ORU health and properly anticipate end of life.

Performance of the New Los Alamos UCN Source and Implications for Future Experiments

NASA Astrophysics Data System (ADS)

Makela, Mark; LANL UCN Team

2017-01-01

The Los Alamos Ultracold Neutron (UCN) source was replaced during this past summer and has been commissioned during the last few months. The new source is the result of lessons learned during the 10 year operation of the first UCN source and extensive Monte Carlo analysis. The new source is a spallation driven source based on a solid deuterium UCN moderator similar the previous one. This talk will present an overview of the new source design and the results of commissioning tests. The talk will conclude with a brief overview of the implications of source performance on the neutron lifetime and LANL nEDM experiments. This work was funded by LANL LDRD.

A fuzzy set approach for reliability calculation of valve controlling electric actuators

NASA Astrophysics Data System (ADS)

Karmachev, D. P.; Yefremov, A. A.; Luneva, E. E.

2017-02-01

The oil and gas equipment and electric actuators in particular frequently perform in various operational modes and under dynamic environmental conditions. These factors affect equipment reliability measures in a vague, uncertain way. To eliminate the ambiguity, reliability model parameters could be defined as fuzzy numbers. We suggest a technique that allows constructing fundamental fuzzy-valued performance reliability measures based on an analysis of electric actuators failure data in accordance with the amount of work, completed before the failure, instead of failure time. Also, this paper provides a computation example of fuzzy-valued reliability and hazard rate functions, assuming Kumaraswamy complementary Weibull geometric distribution as a lifetime (reliability) model for electric actuators.

Prevalence and correlates of electronic cigarette use among adolescents in Greece: a preliminary cross-sectional analysis of nationwide survey data.

PubMed

Fotiou, Anastasios; Kanavou, Eleftheria; Stavrou, Myrto; Richardson, Clive; Kokkevi, Anna

2015-12-01

This study reports the prevalence of electronic cigarette (e-cigarette) use among adolescents in Greece and explores how dual smokers of e-cigarettes and combustible (conventional) cigarettes differ from smokers of only combustible cigarettes across socio-demographic, familial, psychosomatic health and substance use characteristics. Self-reports on smoking were collected from a nationally representative sample of 1320 15-year-old Greek students in the 2014 Health Behaviour in School-aged Children study. Bivariate and multivariable logistic regression analyses were carried out with dependent variables a) lifetime smoking conventional cigarettes and b) lifetime e-cigarette use among lifetime smokers. About 36.9% of 15-year-olds reported lifetime smoking of conventional cigarettes, and 16.6% lifetime use of e-cigarettes, mostly experimenting (0.5% reported current e-cigarette use). Six in 7 ever e-cigarette smokers had smoked conventional cigarettes. Peers who smoke and lifetime cannabis use were significant correlates of both lifetime conventional cigarette and e-cigarette smoking, but more strongly for smoking conventional cigarettes. Alcohol use and low parental monitoring correlated with tobacco smoking but not e-cigarette use. Girls were more likely than boys to report lifetime use of tobacco, but, among lifetime smokers, boys had almost seven times the odds of girls of e-cigarette use. In lifetime smokers, low life satisfaction in females and current smoking of conventional tobacco were independently associated with the experimentation with e-cigarettes. Experimental use of e-cigarettes is relatively widespread among adolescents in Greece. Targeted interventions should focus on male smokers and the role of peer processes and cannabis use in the risk of experimenting with e-cigarettes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Science Data Report for the Optical Properties Monitor (OPM) Experiment

NASA Technical Reports Server (NTRS)

Wilkes, Donald R.; Zwiener, James M.

1999-01-01

Long term stability of spacecraft materials when exposed to the space environment continues to be a major area of investigation. The natural and induced environment surrounding a spacecraft can decrease material performance and limit useful lifetimes. The Optical Properties Monitor (OPM) experiment provided the capability to perform the important flight testing of materials and was flown on the Russian Mir Station to study the long term effects of the natural and induced space environment on materials. The core of the OPM in-flight analysis was three independent optical instruments. These instruments included an integrating sphere spectral reflectometer, a vacuum ultraviolet spectrometer, and a Total Integrated Scatter instrument. The OPM also monitored selected components of the environment including molecular contamination. The OPM was exposed on the exterior of the Mir Docking Module for approximately 8-1/2 months. This report describes the OPM experiment, a brief background of its development, program organization, experiment description, mission overview including space environment definition, performance overview, materials data including flight and ground data, in-depth post flight analysis including ground analysis measurements and a summary discussion of the findings and results.

Building and validating a prediction model for paediatric type 1 diabetes risk using next generation targeted sequencing of class II HLA genes.

PubMed

Zhao, Lue Ping; Carlsson, Annelie; Larsson, Helena Elding; Forsander, Gun; Ivarsson, Sten A; Kockum, Ingrid; Ludvigsson, Johnny; Marcus, Claude; Persson, Martina; Samuelsson, Ulf; Örtqvist, Eva; Pyo, Chul-Woo; Bolouri, Hamid; Zhao, Michael; Nelson, Wyatt C; Geraghty, Daniel E; Lernmark, Åke

2017-11-01

It is of interest to predict possible lifetime risk of type 1 diabetes (T1D) in young children for recruiting high-risk subjects into longitudinal studies of effective prevention strategies. Utilizing a case-control study in Sweden, we applied a recently developed next generation targeted sequencing technology to genotype class II genes and applied an object-oriented regression to build and validate a prediction model for T1D. In the training set, estimated risk scores were significantly different between patients and controls (P = 8.12 × 10 -92 ), and the area under the curve (AUC) from the receiver operating characteristic (ROC) analysis was 0.917. Using the validation data set, we validated the result with AUC of 0.886. Combining both training and validation data resulted in a predictive model with AUC of 0.903. Further, we performed a "biological validation" by correlating risk scores with 6 islet autoantibodies, and found that the risk score was significantly correlated with IA-2A (Z-score = 3.628, P < 0.001). When applying this prediction model to the Swedish population, where the lifetime T1D risk ranges from 0.5% to 2%, we anticipate identifying approximately 20 000 high-risk subjects after testing all newborns, and this calculation would identify approximately 80% of all patients expected to develop T1D in their lifetime. Through both empirical and biological validation, we have established a prediction model for estimating lifetime T1D risk, using class II HLA. This prediction model should prove useful for future investigations to identify high-risk subjects for prevention research in high-risk populations. Copyright © 2017 John Wiley & Sons, Ltd.

Calibration approach for fluorescence lifetime determination for applications using time-gated detection and finite pulse width excitation.

PubMed

Keller, Scott B; Dudley, Jonathan A; Binzel, Katherine; Jasensky, Joshua; de Pedro, Hector Michael; Frey, Eric W; Urayama, Paul

2008-10-15

Time-gated techniques are useful for the rapid sampling of excited-state (fluorescence) emission decays in the time domain. Gated detectors coupled with bright, economical, nanosecond-pulsed light sources like flashlamps and nitrogen lasers are an attractive combination for bioanalytical and biomedical applications. Here we present a calibration approach for lifetime determination that is noniterative and that does not assume a negligible instrument response function (i.e., a negligible excitation pulse width) as does most current rapid lifetime determination approaches. Analogous to a transducer-based sensor, signals from fluorophores of known lifetime (0.5-12 ns) serve as calibration references. A fast avalanche photodiode and a GHz-bandwidth digital oscilloscope is used to detect transient emission from reference samples excited using a nitrogen laser. We find that the normalized time-integrated emission signal is proportional to the lifetime, which can be determined with good reproducibility (typically <100 ps) even for data with poor signal-to-noise ratios ( approximately 20). Results are in good agreement with simulations. Additionally, a new time-gating scheme for fluorescence lifetime imaging applications is proposed. In conclusion, a calibration-based approach is a valuable analysis tool for the rapid determination of lifetime in applications using time-gated detection and finite pulse width excitation.

Assessing the photoaging process at sun exposed and non-exposed skin using fluorescence lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Saito Nogueira, Marcelo; Kurachi, Cristina

2016-03-01

Photoaging is the skin premature aging due to exposure to ultraviolet light, which damage the collagen, elastin and can induce alterations on the skin cells DNA, and, then, it may evolve to precancerous lesions, which are widely investigated by fluorescence spectroscopy and lifetime. The fluorescence spectra and fluorescence lifetime analysis has been presented as a technique of great potential for biological tissue characterization at optical diagnostics. The main targeted fluorophores are NADH (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide), which have free and bound states, each one with different average lifetimes. The average lifetimes for free and bound NADH and FAD change according to tissue metabolic alterations and may contribute to a non-invasive clinical investigation of injuries such as skin lesions. These lesions and the possible areas where they may develop can be interrogated using fluorescence lifetime spectroscopy taking into account the variability of skin phototypes and the changes related to melanin, collagen and elastin, endogenous fluorophores which have emissions that spectrally overlap to the NADH and FAD emission. The objective of this study is to assess the variation on fluorescence lifetimes of normal skin at sun exposed and non-exposed areas and associate this variation to the photoaging process.

Product lifetime, energy efficiency and climate change: A case study of air conditioners in Japan.

PubMed

Nishijima, Daisuke

2016-10-01

This study proposed a modelling technique for estimating life-cycle CO2 emissions of durable goods by considering changes in product lifetime and energy efficiency. The stock and flow of durable goods was modelled by Weibull lifetime distributions and the trend in annual energy efficiency (i.e., annual electricity consumption) of an "average" durable good was formulated as a reverse logistic curve including a technologically critical value (i.e., limit energy efficiency) with respect to time. I found that when the average product lifetime is reduced, there is a trade-off between the reduction in emissions during product use (use phase), due to the additional purchases of new, more energy-efficient air conditioners, and the increase in emissions arising from the additional production of new air conditioners stimulated by the reduction of the average product lifetime. A scenario analysis focused on residential air conditioners in Japan during 1972-2013 showed that for a reduction of average lifetime of 1 year, if the air conditioner energy efficiency limit can be improved by 1.4% from the estimated current efficiency level, then CO2 emissions can be reduced by approximately the same amount as for an extension of average product lifetime of 1 year. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-performance time-resolved fluorescence by direct waveform recording.

PubMed

Muretta, Joseph M; Kyrychenko, Alexander; Ladokhin, Alexey S; Kast, David J; Gillispie, Gregory D; Thomas, David D

2010-10-01

We describe a high-performance time-resolved fluorescence (HPTRF) spectrometer that dramatically increases the rate at which precise and accurate subnanosecond-resolved fluorescence emission waveforms can be acquired in response to pulsed excitation. The key features of this instrument are an intense (1 μJ/pulse), high-repetition rate (10 kHz), and short (1 ns full width at half maximum) laser excitation source and a transient digitizer (0.125 ns per time point) that records a complete and accurate fluorescence decay curve for every laser pulse. For a typical fluorescent sample containing a few nanomoles of dye, a waveform with a signal/noise of about 100 can be acquired in response to a single laser pulse every 0.1 ms, at least 10(5) times faster than the conventional method of time-correlated single photon counting, with equal accuracy and precision in lifetime determination for lifetimes as short as 100 ps. Using standard single-lifetime samples, the detected signals are extremely reproducible, with waveform precision and linearity to within 1% error for single-pulse experiments. Waveforms acquired in 0.1 s (1000 pulses) with the HPTRF instrument were of sufficient precision to analyze two samples having different lifetimes, resolving minor components with high accuracy with respect to both lifetime and mole fraction. The instrument makes possible a new class of high-throughput time-resolved fluorescence experiments that should be especially powerful for biological applications, including transient kinetics, multidimensional fluorescence, and microplate formats.

Treatment evolution and new standards of care: implications for cost-effectiveness analysis.

PubMed

Shechter, Steven M

2011-01-01

Traditional approaches to cost-effectiveness analysis have not considered the downstream possibility of a new standard of care coming out of the research and development pipeline. However, the treatment landscape for patients may change significantly over the course of their lifetimes. To present a Markov modeling framework that incorporates the possibility of treatment evolution into the incremental cost-effectiveness ratio (ICER) that compares treatments available at the present time. . Markov model evaluated by matrix algebra. Measurements. The author evaluates the difference between the new and traditional ICER calculations for patients with chronic diseases facing a lifetime of treatment. The bias of the traditional ICER calculation may be substantial, with further testing revealing that it may be either positive or negative depending on the model parameters. The author also performs probabilistic sensitivity analyses with respect to the possible timing of a new treatment discovery and notes the increase in the magnitude of the bias when the new treatment is likely to appear sooner rather than later. Limitations. The modeling framework is intended as a proof of concept and therefore makes simplifying assumptions such as time stationarity of model parameters and consideration of a single new drug discovery. For diseases with a more active research and development pipeline, the possibility of a new treatment paradigm may be at least as important to consider in sensitivity analysis as other parameters that are often considered.

Measurement of the Average $$B^{0}_{s}$$ Lifetime in the Decay $$B^{0}_{s} \\to J/\\Psi\\Phi$$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pauly, Thilo

2003-01-01

The lifetime difference between the long (CP odd) and short (CP even) lived components of the Bg meson is currently predicted to be of the order of 10 % in the Standard Model. It has been suggested that the decay Bg —>• J/\\|> 4) is predominantly CP even and thus the measured average lifetime could be shorter than the lifetime measured in the inclusive decay modes. We present a measurement of the average lifetime of the 6° meson in its decay Eg —>• J/4> cj), with J/\\|) —> M.+ M.~ and cj) —>• K+K-. During January 2002 and August 2003more » the CDF experiment at the Tevatron has been exposed to about 135 pb" 1 of pp collisions with a centre-of-mass energy of A/S = 1.96 TeV. In the data sample collected with the J/\\Jj dimuon trigger we fully reconstruct about 125 Bg —> J/\\J) (J) candidates with precision silicon information. This is currently the largest exclusive Bg sample. We perform a fit to the proper decay time information to extract the average Bg lifetime and simultaneously use the mass information to disentangle signal from background. For cross-checks we measure the lifetime in the higher statistics modes Bj -» J/\\J> K* and B° —> J/4> K*°, which both have similar decay topologies and kinematics. We obtain r(B°s -> J/\\|> cf>) = (1.31±5:l3(stat.) ± 0.02(syst.)) ps , which is currently the best single measurement of the Bg lifetime and is consistent with other measurements. This result is not accurate enough to establish the existence of a possible significant lifetime difference between the CP odd and even states.« less

Observations and analysis of Alfvén wave phase mixing in the Earth's magnetosphere

NASA Astrophysics Data System (ADS)

Sarris, T. E.; Wright, A. N.; Li, X.

2009-03-01

Signatures of Alfvén wave phase mixing in the Earth's magnetosphere, observed as polarization rotation of a transverse, Pc5 magnetospheric pulsation, are presented and compared to theory. The polarization rotation occurred during a rare event of a dayside narrowband ULF magnetospheric pulsation that lasted for 5 consecutive days, from 24 to 30 November 1997; details of this event were reported by Sarris et al. (2009) through observations at geosynchronous orbit and on the ground. In this paper we investigate the polarization signatures of the pulsation by performing a detailed analysis of its transverse components as observed through hodogram plots. Density measurements from one of the Los Alamos National Laboratory (LANL) spacecraft which had its L shells closest to GOES-8 are used to calculate field line resonance frequencies at geosynchronous orbit; these frequency calculations show good agreement with the observed pulsations but also have a local time offset. For an instance of an observed polarization rotation we estimate the observed poloidal lifetime of the pulsation by the time taken for the poloidal and toroidal amplitudes to become equal, which we compare with the theoretical approximation to the poloidal lifetime, as calculated in a box model magnetosphere by Mann and Wright (1995). Density measurements from different LANL spacecraft at geosynchronous orbit and their varying L shells as derived from their varying local times are used to estimate a local gradient in the local Alfvén speed, which is then used in the calculation of the predicted poloidal lifetime. This is the first time that such polarization rotations are directly observed and compared with theoretical predictions.

Psychological resilience in U.S. military veterans: A 2-year, nationally representative prospective cohort study.

PubMed

Isaacs, Kayla; Mota, Natalie P; Tsai, Jack; Harpaz-Rotem, Ilan; Cook, Joan M; Kirwin, Paul D; Krystal, John H; Southwick, Steven M; Pietrzak, Robert H

2017-01-01

Although many cross-sectional studies have examined the correlates of psychological resilience in U.S. military veterans, few longitudinal studies have identified long-term predictors of resilience in this population. The current prospective cohort study utilized data from a nationally representative sample of 2157 U.S. military veterans who completed web-based surveys in two waves (2011 and 2013) as part of the National Health and Resilience in Veterans Study (NHRVS). Cluster analysis of cumulative lifetime exposure to potentially traumatic events and Wave 2 measures of current symptoms of posttraumatic stress, major depressive, and generalized anxiety disorders was performed to characterize different profiles of current trauma-related psychological symptoms. Different profiles were compared with respect to sociodemographic, clinical, and psychosocial characteristics. A three-group cluster analysis revealed a Control group with low lifetime trauma exposure and low current psychological distress (59.5%), a Resilient group with high lifetime trauma and low current distress (27.4%), and a Distressed group with both high trauma exposure and current distress symptoms (13.1%). These results suggest that the majority of trauma-exposed veterans (67.7%) are psychologically resilient. Compared with the Distressed group, the Resilient group was younger, more likely to be Caucasian, and scored lower on measures of physical health difficulties, past psychiatric history, and substance abuse. Higher levels of emotional stability, extraversion, dispositional gratitude, purpose in life, and altruism, and lower levels of openness to experiences predicted resilient status. Prevention and treatment efforts designed to enhance modifiable factors such as gratitude, sense of purpose, and altruism may help promote resilience in highly trauma-exposed veterans. Published by Elsevier Ltd.

Cost-utility analysis of bariatric surgery compared with conventional medical management in Germany: a decision analytic modeling.

PubMed

Borisenko, Oleg; Mann, Oliver; Duprée, Anna

2017-08-03

The objective was to evaluate cost-utility of bariatric surgery in Germany for a lifetime and 10-year horizon from a health care payer perspective. State-transition Markov model provided absolute and incremental clinical and monetary results. In the model, obese patients could undergo surgery, develop post-surgery complications, experience diabetes type II, cardiovascular diseases or die. German Quality Assurance in Bariatric Surgery Registry and literature sources provided data on clinical effectiveness and safety. The model considered three types of surgeries: gastric bypass, sleeve gastrectomy, and adjustable gastric banding. The model was extensively validated, and deterministic and probabilistic sensitivity analyses were performed to evaluate uncertainty. Cost data were obtained from German sources and presented in 2012 euros (€). Over 10 years, bariatric surgery led to the incremental cost of €2909, generated additional 0.03 years of life and 1.2 quality-adjusted life years (QALYs). Bariatric surgery was cost-effective at 10 years with an incremental cost-effectiveness ratio of €2457 per QALY. Over a lifetime, surgery led to savings of €8522 and generated an increment of 0.7 years of life or 3.2 QALYs. The analysis also depicted an association between surgery and a reduction of obesity-related adverse events (diabetes, cardiovascular disorders). Delaying surgery for up to 3 years, resulted in a reduction of life years and QALYs gained, in addition to a moderate reduction in associated healthcare costs. Bariatric surgery is cost-effective at 10 years post-surgery and may result in a substantial reduction in the financial burden on the healthcare system over the lifetime of the treated individuals. It is also observed that delays in the provision of surgery may lead to a significant loss of clinical benefits.

Metal-Organic Framework Modified Glass Substrate for Analysis of Highly Volatile Chemical Warfare Agents by Paper Spray Mass Spectrometry.

PubMed

Dhummakupt, Elizabeth S; Carmany, Daniel O; Mach, Phillip M; Tovar, Trenton M; Ploskonka, Ann M; Demond, Paul S; DeCoste, Jared B; Glaros, Trevor

2018-03-07

Paper spray mass spectrometry has been shown to successfully analyze chemical warfare agent (CWA) simulants. However, due to the volatility differences between the simulants and real G-series (i.e., sarin, soman) CWAs, analysis from an untreated paper substrate proved difficult. To extend the analytical lifetime of these G-agents, metal-organic frameworks (MOFs) were successfully integrated onto the paper spray substrates to increase adsorption and desorption. In this study, several MOFs and nanoparticles were tested to extend the analytical lifetimes of sarin, soman, and cyclosarin on paper spray substrates. It was found that the addition of either UiO-66 or HKUST-1 to the paper substrate increased the analytical lifetime of the G-agents from less than 5 min detectability to at least 50 min.

FUNDUS AUTOFLUORESCENCE LIFETIMES AND CENTRAL SEROUS CHORIORETINOPATHY

PubMed Central

Dysli, Chantal; Berger, Lieselotte; Wolf, Sebastian

2017-01-01

Purpose: To quantify retinal fluorescence lifetimes in patients with central serous chorioretinopathy (CSC) and to identify disease specific lifetime characteristics over the course of disease. Methods: Forty-seven participants were included in this study. Patients with central serous chorioretinopathy were imaged with fundus photography, fundus autofluorescence, optical coherence tomography, and fluorescence lifetime imaging ophthalmoscopy (FLIO) and compared with age-matched controls. Retinal autofluorescence was excited using a 473-nm blue laser light and emitted fluorescence light was detected in 2 distinct wavelengths channels (498–560 nm and 560–720 nm). Clinical features, mean retinal autofluorescence lifetimes, autofluorescence intensity, and corresponding optical coherence tomography (OCT) images were further analyzed. Results: Thirty-five central serous chorioretinopathy patients with a mean visual acuity of 78 ETDRS letters (range, 50–90; mean Snellen equivalent: 20/32) and 12 age-matched controls were included. In the acute stage of central serous chorioretinopathy, retinal fluorescence lifetimes were shortened by 15% and 17% in the respective wavelength channels. Multiple linear regression analysis showed that fluorescence lifetimes were significantly influenced by the disease duration (P < 0.001) and accumulation of photoreceptor outer segments (P = 0.03) but independent of the presence or absence of subretinal fluid. Prolonged central macular autofluorescence lifetimes, particularly in eyes with retinal pigment epithelial atrophy, were associated with poor visual acuity. Conclusion: This study establishes that autofluorescence lifetime changes occurring in central serous chorioretinopathy exhibit explicit patterns which can be used to estimate perturbations of the outer retinal layers with a high degree of statistical significance. PMID:28099314

Expanding the potential of standard flow cytometry by extracting fluorescence lifetimes from cytometric pulse shifts

PubMed Central

Cao, Ruofan; Naivar, Mark A; Wilder, Mark; Houston, Jessica P

2014-01-01

Fluorescence lifetime measurements provide information about the fluorescence relaxation, or intensity decay, of organic fluorophores, fluorescent proteins, and other inorganic molecules that fluoresce. The fluorescence lifetime is emerging in flow cytometry and is helpful in a variety of multiparametric, single cell measurements because it is not impacted by nonlinearity that can occur with fluorescence intensity measurements. Yet time-resolved cytometry systems rely on major hardware modifications making the methodology difficult to reproduce. The motivation of this work is, by taking advantage of the dynamic nature of flow cytometry sample detection and applying digital signal processing methods, to measure fluorescence lifetimes using an unmodified flow cytometer. We collect a new lifetime-dependent parameter, referred to herein as the fluorescence-pulse-delay (FPD), and prove it is a valid representation of the average fluorescence lifetime. To verify we generated cytometric pulses in simulation, with light emitting diode (LED) pulsation, and with true fluorescence measurements of cells and microspheres. Each pulse is digitized and used in algorithms to extract an average fluorescence lifetime inherent in the signal. A range of fluorescence lifetimes is measurable with this approach including standard organic fluorophore lifetimes (∼1 to 22 ns) as well as small, simulated shifts (0.1 ns) under standard conditions (reported herein). This contribution demonstrates how digital data acquisition and signal processing can reveal time-dependent information foreshadowing the exploitation of full waveform analysis for quantification of similar photo-physical events within single cells. © 2014 The Authors. Published by Wiley Periodicals, Inc. PMID:25274073

Emotional Support, Negative Interaction and DSM IV Lifetime Disorders among Older African Americans: Findings from the National Survey of American Life (NSAL)

PubMed Central

Lincoln, Karen D.; Taylor, Robert Joseph; Bullard, Kai McKeever; Chatters, Linda M.; Himle, Joseph A.; Woodward, Amanda Toler; Jackson, James S.

2010-01-01

Objectives Both emotional support and negative interaction with family members have been linked to mental health. However, few studies have examined the associations between emotional support and negative interaction and psychiatric disorders in late life. This study investigated the relationship between emotional support and negative interaction on lifetime prevalence of mood and anxiety disorders among older African Americans. Design The analyses utilized the National Survey of American Life. Methods Logistic regression and negative binomial regression analyses were used to examine the effect of emotional support and negative interaction with family members on the prevalence of lifetime DSM-IV mood and anxiety disorders. Participants Data from 786 African Americans aged 55 years and older were used. Measurement The DSM-IV World Mental Health Composite International Diagnostic Interview (WMH-CIDI) was used to assess mental disorders. Three dependent variables were investigated: the prevalence of lifetime mood disorders, the prevalence of lifetime anxiety disorders, and the total number of lifetime mood and anxiety disorders. Results Multivariate analysis found that emotional support was not associated with any of the three dependent variables. Negative interaction was significantly and positively associated with the odds of having a lifetime mood disorder, a lifetime anxiety disorder and the number of lifetime mood and anxiety disorders. Conclusions This is the first study to investigate the relationship between emotional support, negative interaction with family members and psychiatric disorders among older African Americans. Negative interaction was a risk factor for mood and anxiety disorders among older African Americans, whereas emotional support was not significant. PMID:20157904

Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sulas, Dana B.; London, Alexander E.; Huang, Lifeng

Infrared organic photodetector materials are investigated using transient absorption spectroscopy, demonstrating that ultrafast charge generation assisted by polymer aggregation is essential to compensate for the energy gap law, which dictates that excited state lifetimes decrease as the band gap narrows. Short sub–picosecond singlet exciton lifetimes are measured in a structurally related series of infrared–absorbing copolymers that consist of alternating cyclopentadithiophene electron–rich “push” units and strong electron–deficient “pull” units, including benzothiadiazole, benzoselenadiazole, pyridalselenadiazole, or thiadiazoloquinoxaline. While the ultrafast lifetimes of excitons localized on individual polymer chains suggest that charge carrier generation will be inefficient, high detectivity for polymer:PC 71BM infrared photodetectorsmore » is measured in the 0.6 < λ < 1.5 µm range. The photophysical processes leading to charge generation are investigated by performing a global analysis on transient absorption data of blended polymer:PC 71BM films. In these blends, charge carriers form primarily at polymer aggregate sites on the ultrafast time scale (within our instrument response), leaving quickly decaying single–chain excitons unquenched. Lastly, the results have important implications for the further development of organic infrared optoelectronic devices, where targeting processes such as excited state delocalization over aggregates may be necessary to mitigate losses to ultrafast exciton decay as materials with even lower band gaps are developed.« less

Preferential Charge Generation at Aggregate Sites in Narrow Band Gap Infrared Photoresponsive Polymer Semiconductors

DOE PAGES

Sulas, Dana B.; London, Alexander E.; Huang, Lifeng; ...

2018-02-13

Infrared organic photodetector materials are investigated using transient absorption spectroscopy, demonstrating that ultrafast charge generation assisted by polymer aggregation is essential to compensate for the energy gap law, which dictates that excited state lifetimes decrease as the band gap narrows. Short sub–picosecond singlet exciton lifetimes are measured in a structurally related series of infrared–absorbing copolymers that consist of alternating cyclopentadithiophene electron–rich “push” units and strong electron–deficient “pull” units, including benzothiadiazole, benzoselenadiazole, pyridalselenadiazole, or thiadiazoloquinoxaline. While the ultrafast lifetimes of excitons localized on individual polymer chains suggest that charge carrier generation will be inefficient, high detectivity for polymer:PC 71BM infrared photodetectorsmore » is measured in the 0.6 < λ < 1.5 µm range. The photophysical processes leading to charge generation are investigated by performing a global analysis on transient absorption data of blended polymer:PC 71BM films. In these blends, charge carriers form primarily at polymer aggregate sites on the ultrafast time scale (within our instrument response), leaving quickly decaying single–chain excitons unquenched. Lastly, the results have important implications for the further development of organic infrared optoelectronic devices, where targeting processes such as excited state delocalization over aggregates may be necessary to mitigate losses to ultrafast exciton decay as materials with even lower band gaps are developed.« less

Cutting force measurement of electrical jigsaw by strain gauges

NASA Astrophysics Data System (ADS)

Kazup, L.; Varadine Szarka, A.

2016-11-01

This paper describes a measuring method based on strain gauges for accurate specification of electric jigsaw's cutting force. The goal of the measurement is to provide an overall perspective about generated forces in a jigsaw's gearbox during a cutting period. The lifetime of the tool is affected by these forces primarily. This analysis is part of the research and development project aiming to develop a special linear magnetic brake for realizing automatic lifetime tests of electric jigsaws or similar handheld tools. The accurate specification of cutting force facilitates to define realistic test cycles during the automatic lifetime test. The accuracy and precision resulted by the well described cutting force characteristic and the possibility of automation provide new dimension for lifetime testing of the handheld tools with alternating movement.

Factors associated with HIV among female sex workers in a high HIV prevalent state of India.

PubMed

Medhi, Gajendra Kumar; Mahanta, Jagadish; Paranjape, Ramesh S; Adhikary, Rajatashuvra; Laskar, Nabjyoti; Ngully, P

2012-01-01

The study was carried out to assess the factors associated with HIV seropositivity among female sex workers (FSWs) in Dimapur, Nagaland, a high HIV prevalence state of India. A total of 426 FSWs were recruited into the study using respondent driven sampling (RDS). Data on demographic characteristics, sexual and injecting risk behaviours were collected from them and were tested for HIV, Syphilis, Neisseria gonorrhoeae and Chlamydia trachomatis. RDS-weighted univariate and multivariate logistic regression analysis was performed to assess the factors associated with HIV seropositivity. Consistent condom use with regular and occasional sexual clients was 9% and 16.4%, respectively. About 25% of the participants ever used and 5.7% ever injected illicit drugs. RDS adjusted HIV prevalence was 11.6%. In the univariate analysis, factors associated with HIV were initiating sexual intercourse before the age of 15 years, ≥2 years duration of sex work, serving clients at lodge/hotel, positive test result for one or more sexually transmitted infections (STIs), lifetime history of injecting drug use, lifetime history of consuming illicit drugs, ever having exchanged sex for drugs, having sexual partners who engaged in risky injecting practices and having been widowed or divorced. In multivariate analysis, factors found to be independently associated with HIV included lifetime injecting drug use, initiating sexual intercourse before the age of 15 years, positive test result for one or more STIs and having been widowed. Injecting drug use was found to be most potent independent risk factor for HIV (OR: 3.17, CI: 1.02-9.89). Because of lower consistent condom use among them, FSWs may act as bridge for HIV transmission to general population from injecting drug users (IDU) through their sexual clients. The informations from this study may be useful for enriching the HIV preventions effort for FSWs in this region.

Air Intake Performance of Air Breathing Ion Engines

NASA Astrophysics Data System (ADS)

Fujita, Kazuhisa

The air breathing ion engine (ABIE) is a new type of electric propulsion system which can be used to compensate the aerodynamic drag of the satellite orbiting at extremely low altitudes. In this propulsion system, the low-density atmosphere surrounding the satellite is taken in and used as the propellant of ion engines to reduce the propellant mass for a long operation lifetime. Since feasibility and performance of the ABIE are subject to the compression ratio and the air intake efficiency, a numerical analysis has been conducted by means of the direct-simulation Monte-Carlo method to clarify the characteristics of the air-intake performance in highly rarefied flows. Influences of the flight altitude, the aspect-ratio of the air intake duct, the angle of attack, and the wall conditions are investigated.

Comparison of SIRTF dewar performance in the 900 km and 100,000 km orbits

NASA Technical Reports Server (NTRS)

Lee, J. H.; Maa, S. S.; Ng, Y. S.

1990-01-01

Feasibility studies showed that the Space Infrared Telescope Facility (SIRTF) can be launched into a 100,000-km high earth orbit (HEO) using a Titan/Centaur launch vehicle. This paper compares the performance of an all-superfluid helium dewar system for SIRTF under conditions of the LEO (900-km) and the HEO missions. Results show that the SIRTF all-superfluid He dewar can achieve a 5-yr lifetime for the 100,000 km HEO mission, with 20 percent margin. Methods to achieve further enhancement of dewar lifetime for the HEO mission are suggested.

Ageing management of french NPP civil work structures

NASA Astrophysics Data System (ADS)

Gallitre, E.; Dauffer, D.

2011-04-01

This paper presents EDF practice about concrete structure ageing management, from the mechanisms analysis to the formal procedure which allows the French company to increase 900 MWe NPP lifetime until 40 years; it will also introduce its action plan for 60 years lifetime extension. This practice is based on a methodology which identifies every ageing mechanism; both plants feedback and state of the art are screened and conclusions are drawn up into an "ageing analysis data sheet". That leads at first to a collection of 57 data sheets which give the mechanism identification, the components that are concerned and an analysis grid which is designed to assess the safety risk. This analysis screens the reference documents describing the mechanism, the design lifetime hypotheses, the associated regulation or codification, the feedback experiences, the accessibility, the maintenance actions, the repair possibility and so one. This analysis has to lead to a conclusion about the risk taking into account monitoring and maintenance. If the data sheet conclusion is not clear enough, then a more detailed report is launched. The technical document which is needed, is a formal detailed report which summarizes every theoretical knowledge and monitoring data: its objective is to propose a solution for ageing management: this solution can include more inspections or specific research development, or additional maintenance. After a first stage on the 900 MWe units, only two generic ageing management detailed reports have been needed for the civil engineering part: one about reactor building containment, and one about other structures which focuses on concrete inflating reactions. The second stage consists on deriving this generic analysis (ageing mechanism and detailed reports) to every plant where a complete ageing report is required (one report for all equipments and structures of the plant, but specific for each reactor). This ageing management is a continuous process because the 57 generic data sheets set is updated every year and the detailed generic reports every five years. After this 40 year lifetime extension, EDF is preparing a 60 years lifetime action plan which includes R&D actions, specific industrial studies and also monitoring improvements.

Predictors of Decision-Making on the Iowa Gambling Task: Independent Effects of Lifetime History of Substance Use Disorders and Performance on the Trail Making Test

ERIC Educational Resources Information Center

Barry, D.; Petry, N. M.

2008-01-01

Poor decision-making and executive function deficits are frequently observed in individuals with substance use disorders (SUDs), and executive deficits may contribute to poor decision-making in this population. This study examined the influence of lifetime history of an alcohol, cocaine, heroin, or polysubstance use disorder on decision-making as…

Enhanced Lifetime of Polymer Solar Cells by Surface Passivation of Metal Oxide Buffer Layers.

PubMed

Venkatesan, Swaminathan; Ngo, Evan; Khatiwada, Devendra; Zhang, Cheng; Qiao, Qiquan

2015-07-29

The role of electron selective interfaces on the performance and lifetime of polymer solar cells were compared and analyzed. Bilayer interfaces consisting of metal oxide films with cationic polymer modification namely poly ethylenimine ethoxylated (PEIE) were found to enhance device lifetime compared to bare metal oxide films when used as an electron selective cathode interface. Devices utilizing surface-modified metal oxide layers showed enhanced lifetimes, retaining up to 85% of their original efficiency when stored in ambient atmosphere for 180 days without any encapsulation. The work function and surface potential of zinc oxide (ZnO) and ZnO/PEIE interlayers were evaluated using Kelvin probe and Kelvin probe force microscopy (KPFM) respectively. Kelvin probe measurements showed a smaller reduction in work function of ZnO/PEIE films compared to bare ZnO films when aged in atmospheric conditions. KPFM measurements showed that the surface potential of the ZnO surface drastically reduces when stored in ambient air for 7 days because of surface oxidation. Surface oxidation of the interface led to a substantial decrease in the performance in aged devices. The enhancement in the lifetime of devices with a bilayer interface was correlated to the suppressed surface oxidation of the metal oxide layers. The PEIE passivated surface retained a lower Fermi level when aged, which led to lower trap-assisted recombination at the polymer-cathode interface. Further photocharge extraction by linearly increasing voltage (Photo-CELIV) measurements were performed on fresh and aged samples to evaluate the field required to extract maximum charges. Fresh devices with a bare ZnO cathode interlayer required a lower field than devices with ZnO/PEIE cathode interface. However, aged devices with ZnO required a much higher field to extract charges while aged devices with ZnO/PEIE showed a minor increase compared to the fresh devices. Results indicate that surface modification can act as a suitable passivation layer to suppress oxidation in metal oxide thin films for enhanced lifetime in inverted organic solar cells.

Genetic, environmental and interaction effects on lifetime production efficiency of crossbred ewes.

PubMed

Saoud, N B; Hohenboken, W D

1984-09-01

A total of 399 crossbred ewes born in 2 yr were maintained either on irrigated or dryland hill pastures. The ewes were sired by North Country Cheviot, Dorset, Finnsheep or Romney rams mated to Suffolk or Columbia-type ewes. The crossbred ewes were mated to Hampshire rams throughout the study and had the opportunity for either 4 or 5 yr of production. Annual feed cost was calculated based upon estimated annual metabolizable energy (ME) requirements for maintenance, ewe growth, pregnancy and lactation. Income from weaned feeder lambs and from orphan lambs sold shortly after birth, feed cost and net revenue were analyzed during each ewe's first production year, as well as for the entire period of the experiment. Crossbred group significantly affected income from lambs produced, feed cost and net revenue for the ewes' first production year. Crossbred group and crossbred group X management system interactions generally influenced lifetime income from lambs produced and from orphans sold, gross income, total cost and net revenue per ewe. Finnsheep X Suffolk ewes performed best on irrigated pastures but were below average for lifetime net revenue on hill pastures. Finnsheep X Columbia ewes performed best on hill pastures and, with Dorset X Suffolk and Dorset X Columbia ewes, were well above average for lifetime net revenue on irrigated pastures as well. Suffolk crossbreds consistently performed better on irrigated than on hill pastures. While most ewes with Columbia-type inheritance were more efficient on hill than on irrigated pastures, this result was not always consistent.

Advances in 193 nm excimer lasers for mass spectrometry applications

NASA Astrophysics Data System (ADS)

Delmdahl, Ralph; Esser, Hans-Gerd; Bonati, Guido

2016-03-01

Ongoing progress in mass analysis applications such as laser ablation inductively coupled mass spectrometry of solid samples and ultraviolet photoionization mediated sequencing of peptides and proteins is to a large extent driven by ultrashort wavelength excimer lasers at 193 nm. This paper will introduce the latest improvements achieved in the development of compact high repetition rate excimer lasers and elaborate on the impact on mass spectrometry instrumentation. Various performance and lifetime measurements obtained in a long-term endurance test over the course of 18 months will be shown and discussed in view of the laser source requirements of different mass spectrometry tasks. These sampling type applications are served by excimer lasers delivering pulsed 193 nm output of several mJ as well as fast repetition rates which are already approaching one Kilohertz. In order to open up the pathway from the laboratory to broader market industrial use, sufficient component lifetimes and long-term stable performance behavior have to be ensured. The obtained long-term results which will be presented are based on diverse 193 nm excimer laser tube improvements aiming at e.g. optimizing the gas flow dynamics and have extended the operational life the laser tube for the first time over several billion pulses even under high duty-cycle conditions.

Understanding the prevalence of lifetime abstinence from alcohol: An ecological study.

PubMed

Probst, Charlotte; Manthey, Jakob; Rehm, Jürgen

2017-09-01

The level of alcohol consumption and related burden in a country are strongly impacted by the prevalence of abstinence from alcohol use. The objective of this study was to characterize the association of lifetime abstinence from alcohol use with economic wealth (as measured in the gross domestic product [GDP]) and Muslim religion on a country level. An ecological study was performed using aggregate data of 183 countries for the year 2010. Lifetime abstinence among men and women was predicted using fractional response regression models with the natural logarithm of GDP-PPP (purchasing power parity) and the proportion of Muslim population as predictors. The models were further adjusted by the country's median age and World Health Organization region. Precision of prediction was investigated. Descriptive analyses showed a strong negative association between GDP-PPP and lifetime abstinence in countries without a Muslim majority and a GDP-PPP up to 20,000 international dollars. Regression models confirmed the negative association with GDP-PPP and showed a strong positive association between lifetime abstinence and the proportion of Muslim population. Stratified sensitivity analyses showed that in countries without a Muslim majority only GDP-PPP showed a statistically significant association whereas in Muslim majority countries only the proportion of Muslims was associated with the prevalence of lifetime abstinence. Particularly in countries with a lower GDP and without Muslim majority the prevalence of lifetime abstinence from alcohol use is strongly negatively associated with GDP-PPP. Future research should analyze the accordance in trends of GDP and lifetime abstinence over time. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluorescence lifetime imaging of calcium flux in neurons in response to pulsed infrared light

NASA Astrophysics Data System (ADS)

Walsh, Alex J.; Sedelnikova, Anna; Tolstykh, Gleb P.; Ibey, Bennett L.; Beier, Hope T.

2017-02-01

Pulsed infrared light can excite action potentials in neurons; yet, the fundamental mechanism underlying this phenomenon is unknown. Previous work has observed a rise in intracellular calcium concentration following infrared exposure, but the source of the calcium and mechanism of release is unknown. Here, we used fluorescence lifetime imaging of Oregon Green BAPTA-1 to study intracellular calcium dynamics in primary rat hippocampal neurons in response to infrared light exposure. The fluorescence lifetime of Oregon Green BAPTA-1 is longer when bound to calcium, and allows robust measurement of intracellular free calcium concentrations. First, a fluorescence lifetime calcium calibration curve for Oregon Green BAPTA-1 was determined in solutions. The normalized amplitude of the short and long lifetimes was calibrated to calcium concentration. Then, neurons were incubated in Oregon Green BAPTA-1 and exposed to pulses of infrared light (0-1 J/cm2; 0-5 ms; 1869 nm). Fluorescence lifetime images were acquired prior to, during, and after the infrared exposure. Fluorescence lifetime images, 64x64 pixels, were acquired at 12 or 24 ms for frame rates of 83 and 42 Hz, respectively. Accurate α1 approximations were achieved in images with low photon counts by computing an α1 index value from the relative probability of the observed decay events. Results show infrared light exposure increases intracellular calcium in neurons. Altogether, this study demonstrates accurate fluorescence lifetime component analysis from low-photon count data for improved imaging speed.

Cost-effectiveness of unicompartmental compared with total knee replacement: a population-based study using data from the National Joint Registry for England and Wales

PubMed Central

Liddle, Alexander D; Hamilton, Thomas W; Judge, Andrew; Pandit, Hemant G; Murray, David W; Pinedo-Villanueva, Rafael

2018-01-01

Objectives To assess the value for money of unicompartmental knee replacement (UKR) compared with total knee replacement (TKR). Design A lifetime Markov model provided the framework for the analysis. Setting Data from the National Joint Registry (NJR) for England and Wales primarily informed the analysis. Participants Propensity score matched patients in the NJR who received either a UKR or TKR. Interventions UKR is a less invasive alternative to TKR, where only the compartment affected by osteoarthritis is replaced. Primary outcome measures Incremental quality-adjusted life years (QALYs) and healthcare system costs. Results The provision of UKR is expected to lead to a gain in QALYs compared with TKR for all age and gender subgroups (male: <60 years: 0.12, 60–75 years: 0.20, 75+ years: 0.19; female: <60 years: 0.10, 60–75 years: 0.28, 75+ years: 0.44) and a reduction in costs (male: <60: £−1223, 60–75 years: £−1355, 75+ years: £−2005; female: <60 years: £−601, 60–75 years: £−935, 75+ years: £−1102 per patient over the lifetime). UKR is expected to lead to a reduction in QALYs compared with TKR when performed by surgeons with low UKR utilisation but an increase among those with high utilisation (<10%, median 6%: −0.04, ≥10%, median 27%: 0.26). Regardless of surgeon usage, costs associated with UKR are expected to be lower than those of TKR (<10%: £−127, ≥10%: £−758). Conclusions UKR can be expected to generate better health outcomes and lower lifetime costs than TKR. Surgeon usage of UKR does, however, have a significant impact on the cost-effectiveness of the procedure. To achieve the best results, surgeons need to perform a sufficient proportion of knee replacements as UKR. Low usage surgeons may therefore need to broaden their indications for UKR. PMID:29706598

Probabilistic material strength degradation model for Inconel 718 components subjected to high temperature, high-cycle and low-cycle mechanical fatigue, creep and thermal fatigue effects

NASA Technical Reports Server (NTRS)

Bast, Callie C.; Boyce, Lola

1995-01-01

This report presents the results of both the fifth and sixth year effort of a research program conducted for NASA-LeRC by The University of Texas at San Antonio (UTSA). The research included on-going development of methodology for a probabilistic material strength degradation model. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes five effects that typically reduce lifetime strength: high temperature, high-cycle mechanical fatigue, low-cycle mechanical fatigue, creep and thermal fatigue. Statistical analysis was conducted on experimental Inconel 718 data obtained from the open literature. This analysis provided regression parameters for use as the model's empirical material constants, thus calibrating the model specifically for Inconel 718. Model calibration was carried out for five variables, namely, high temperature, high-cycle and low-cycle mechanical fatigue, creep and thermal fatigue. Methodology to estimate standard deviations of these material constants for input into the probabilistic material strength model was developed. Using an updated version of PROMISS, entitled PROMISS93, a sensitivity study for the combined effects of high-cycle mechanical fatigue, creep and thermal fatigue was performed. Then using the current version of PROMISS, entitled PROMISS94, a second sensitivity study including the effect of low-cycle mechanical fatigue, as well as, the three previous effects was performed. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing a combination of high-cycle mechanical fatigue and high temperature effects by model to the combination by experiment were conducted. Thus, for Inconel 718, the basic model assumption of independence between effects was evaluated. Results from this limited verification study strongly supported this assumption.

LCP- LIFETIME COST AND PERFORMANCE MODEL FOR DISTRIBUTED PHOTOVOLTAIC SYSTEMS

NASA Technical Reports Server (NTRS)

Borden, C. S.

1994-01-01

The Lifetime Cost and Performance (LCP) Model was developed to assist in the assessment of Photovoltaic (PV) system design options. LCP is a simulation of the performance, cost, and revenue streams associated with distributed PV power systems. LCP provides the user with substantial flexibility in specifying the technical and economic environment of the PV application. User-specified input parameters are available to describe PV system characteristics, site climatic conditions, utility purchase and sellback rate structures, discount and escalation rates, construction timing, and lifetime of the system. Such details as PV array orientation and tilt angle, PV module and balance-of-system performance attributes, and the mode of utility interconnection are user-specified. LCP assumes that the distributed PV system is utility grid interactive without dedicated electrical storage. In combination with a suitable economic model, LCP can provide an estimate of the expected net present worth of a PV system to the owner, as compared to electricity purchased from a utility grid. Similarly, LCP might be used to perform sensitivity analyses to identify those PV system parameters having significant impact on net worth. The user describes the PV system configuration to LCP via the basic electrical components. The module is the smallest entity in the PV system which is modeled. A PV module is defined in the simulation by its short circuit current, which varies over the system lifetime due to degradation and failure. Modules are wired in series to form a branch circuit. Bypass diodes are allowed between modules in the branch circuits. Branch circuits are then connected in parallel to form a bus. A collection of buses is connected in parallel to form an increment to capacity of the system. By choosing the appropriate series-parallel wiring design, the user can specify the current, voltage, and reliability characteristics of the system. LCP simulation of system performance is site-specific and follows a three-step procedure. First the hourly power produced by the PV system is computed using a selected year's insolation and temperature profile. For this step it is assumed that there are no module failures or degradation. Next, the monthly simulation is performed involving a month to month progression through the lifetime of the system. In this step, the effects of degradation, failure, dirt accumulation and operations/maintenance efforts on PV system performance over time are used to compute the monthly power capability fraction. The resulting monthly power capability fractions are applied to the hourly power matrix from the first step, giving the anticipated hourly energy output over the lifetime of the system. PV system energy output is compared with the PV system owner's electricity demand for each hour. The amount of energy to be purchased from or sold to the utility grid is then determined. Monthly expenditures on the PV system and the purchase of electricity from the utility grid are also calculated. LCP generates output reports pertaining to the performance of the PV system, and system costs and revenues. The LCP model, written in SIMSCRIPT 2.5 for batch execution on an IBM 370 series computer, was developed in 1981.

A study of structural concepts for ultralightweight spacecraft

NASA Technical Reports Server (NTRS)

Miller, R. K.; Knapp, K.; Hedgepeth, J. M.

1984-01-01

Structural concepts for ultralightweight spacecraft were studied. Concepts for ultralightweight space structures were identified and the validity of heir potential application in advanced spacecraft was assessed. The following topics were investigated: (1) membrane wrinkling under pretensioning; (2) load-carrying capability of pressurized tubes; (3) equilibrium of a precompressed rim; (4) design of an inflated reflector spacecraft; (5) general instability of a rim; and (6) structural analysis of a pressurized isotensoid column. The design approaches for a paraboloidal reflector spacecraft included a spin-stiffened design, both inflated and truss central columns, and to include both deep truss and rim-stiffened geodesic designs. The spinning spacecraft analysis is included, and the two truss designs are covered. The performances of four different approaches to the structural design of a paraboloidal reflector spacecraft are compared. The spinning and inflated configurations result in very low total masses and some concerns about their performance due to unresolved questions about dynamic stability and lifetimes, respectively.

Interpretation of measurements of dynamic fluorescence of the eye

NASA Astrophysics Data System (ADS)

Schweitzer, Dietrich; Hammer, Martin; Jentsch, Susanne; Schenke, Stefan

2007-09-01

First pathological alterations occur at cellular level, most in metabolism. An indirect estimation of metabolic activity in cells is measurement of microcirculation. Measurements of tissue autofluorescence are potentially suited for direct investigation of cellular metabolism. Besides redox pairs of co-enzymes (NADH-NAD, FADH2-FAD) several other fluorophores are excited in tissue. In addition, a number of anatomical structures are simultaneously excited, when investigating the eye-ground. In this study, spectral and time resolved comparison was performed between purified substances, single ocular structures and in vivo measurements of the time-resolved autofluorescence at the human eye. In human eyes, the ageing pigment lipofuscin covers other fluorophores at the fundus in long - wave visible range. Applying lifetime measurements, weakly emitting fluorophores can be detected, when the lifetimes are different from the strongly emitting fluorophore. For this, the autofluorescence was excited at 468 nm and detected in two spectral ranges (500 nm-560 nm, 560 nm-700 nm). In tri-exponential fitting, the short lifetime corresponds to retinal pigment epithelium, the mean lifetime corresponds probably to neural retina and the long lifetime is caused by fluorescence of connective tissue.

A /sup 1/Pi--X /sup 1/. sigma. /sup +/ band system in CH/sup +/ and CD/sup +/: theoretical spectroscopic constants and lifetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elander, N.; Oddershede, J.; Beebe, N.H.F.

1977-08-15

Polarization propagator calculation of spectroscopic constants and radiative lifetimes for the A /sup 1/Pi--X /sup 1/..sigma../sup +/ band system are presented. The spectroscopic constants agree well with experimental and other theoretical values. We have also performed an iterative Rydberg-Klein-Rees (RKR) calculation of B/sub e/, ..omega../sub e/, and ..omega../sub e/x/sub e/ for the experimental X /sup 1/..sigma../sup +/ state.The calculated radiative lifetime for the A /sup 1/Pi state (v'=0) is 660 ns and 598 ns, with theoretical and experimental potential energy curves, respectively. This difference (about 60 ns) indicates the inaccuracy in the present calculation. Experimentally the most recent estimate ofmore » the A /sup 1/Pi (v'=0) state is 630 +- 50 ns, and theoretically the Yoshimine et al. transition moment gives tau (A /sup 1/Pi, v'=0) =722 ns.The radiative lifetimes calculated for CD/sup +/ are between 1.3% and 3.9% larger than the corresponding CH/sup +/ lifetimes.« less

Modulated electron-multiplied fluorescence lifetime imaging microscope: all-solid-state camera for fluorescence lifetime imaging.

PubMed

Zhao, Qiaole; Schelen, Ben; Schouten, Raymond; van den Oever, Rein; Leenen, René; van Kuijk, Harry; Peters, Inge; Polderdijk, Frank; Bosiers, Jan; Raspe, Marcel; Jalink, Kees; Geert Sander de Jong, Jan; van Geest, Bert; Stoop, Karel; Young, Ian Ted

2012-12-01

We have built an all-solid-state camera that is directly modulated at the pixel level for frequency-domain fluorescence lifetime imaging microscopy (FLIM) measurements. This novel camera eliminates the need for an image intensifier through the use of an application-specific charge coupled device design in a frequency-domain FLIM system. The first stage of evaluation for the camera has been carried out. Camera characteristics such as noise distribution, dark current influence, camera gain, sampling density, sensitivity, linearity of photometric response, and optical transfer function have been studied through experiments. We are able to do lifetime measurement using our modulated, electron-multiplied fluorescence lifetime imaging microscope (MEM-FLIM) camera for various objects, e.g., fluorescein solution, fixed green fluorescent protein (GFP) cells, and GFP-actin stained live cells. A detailed comparison of a conventional microchannel plate (MCP)-based FLIM system and the MEM-FLIM system is presented. The MEM-FLIM camera shows higher resolution and a better image quality. The MEM-FLIM camera provides a new opportunity for performing frequency-domain FLIM.

Cross-shell excitations from the f p shell: Lifetime measurements in 61Zn

NASA Astrophysics Data System (ADS)

Queiser, M.; Vogt, A.; Seidlitz, M.; Reiter, P.; Togashi, T.; Shimizu, N.; Utsuno, Y.; Otsuka, T.; Honma, M.; Petkov, P.; Arnswald, K.; Altenkirch, R.; Birkenbach, B.; Blazhev, A.; Braunroth, T.; Dewald, A.; Eberth, J.; Fransen, C.; Fu, B.; Hess, H.; Hetzenegger, R.; Hirsch, R.; Jolie, J.; Karayonchev, V.; Kaya, L.; Lewandowski, L.; Müller-Gatermann, C.; Régis, J.-M.; Rosiak, D.; Schneiders, D.; Siebeck, B.; Steinbach, T.; Wolf, K.; Zell, K.-O.

2017-10-01

Lifetimes of excited states in the neutron-deficient nucleus 61Zn were measured employing the recoil-distance Doppler-shift (RDDS) and the electronic fast-timing methods at the University of Cologne. The nucleus of interest was populated as an evaporation residue in 40Ca(24Mg,n 2 p )61Zn and 58Ni(α ,n )61Zn reactions at 67 and 19 MeV, respectively. Five lifetimes were measured for the first time, including the lifetime of the 5 /21- isomer at 124 keV. Short lifetimes from the RDDS analysis are corrected for Doppler-shift attenuation (DSA) in the target and stopper foils. Ambiguous observations in previous measurements were resolved. The obtained lifetimes are compared to predictions from different sets of shell-model calculations in the f p , f5 /2p g9 /2 , and multishell f p -g9 /2d5 /2 model spaces. The band built on the 9 /21+ state exhibits a prolate deformation with β ≈0.24 . Especially, the inclusion of cross-shell excitation into the 1 d5 /2 orbital is found to be decisive for the description of collectivity in the first excited positive-parity band.

NOx Lifetime During WINTER

NASA Astrophysics Data System (ADS)

Kenagy, H. S.; Sparks, T.; Ebben, C. J.; Wooldridge, P. J.; Lopez-Hilfiker, F.; Lee, B. H.; Thornton, J. A.; McDuffie, E. E.; Fibiger, D. L.; Brown, S. S.; Montzka, D. D.; Weinheimer, A. J.; Apel, E. C.; Jaegle, L.; Cohen, R. C.

2017-12-01

The study of the lifetime and fate of NOx (=NO + NO2) is important for understanding its persistence and distribution. This requires an understanding of the balance of NOx sinks. Although urban NOx lifetimes are relatively well understood during summertime conditions, wintertime NOx chemistry has been comparatively less studied. We used measurements of NOx and its oxidation products from the aircraft-based WINTER (Wintertime INvestigation of Transport, Emissions, and Reactivity) campaign over the northeastern US during February-March 2015 to help constrain NOx lifetime during wintertime conditions when days are shorter, actinic flux is reduced, and temperatures are colder. By analyzing the marine outflow from the NYC-DC corridor, we learn that wintertime NOx has a long lifetime, is much longer-lived during the day than at night, and its lifetime is controlled during both periods by NOx conversion to nitric acid (HNO3) as the primary NOx sink. We also employ a two-box model to constrain the wintertime plume dilution rate and HNO3 deposition rate. Additionally, analysis of the nighttime Ox budget suggests that approximately 10% of O3 is lost overnight through N2O5 dark reactions that produce HNO3.

Practicing DSAM in aberrant domain: use of multi-disciplinary techniques

NASA Astrophysics Data System (ADS)

Das, S.; Samanta, S.; Bhattacharjee, R.; Raut, R.; Ghugre, S. S.; Sinha, A. K.; Garg, U.; Chakrabarti, R.; Mukhopadhyay, S.; Madhavan, N.; Muralithar, S.; Singh, R. P.; Sethi, J.; Saha, S.; Palit, R.

2016-10-01

Measurement of level lifetime of nuclear states is of relevance in nuclear structure research as it provides us with an unique probe into the underlying microscopic structure of these states. Of the several experimental techniques for lifetime measurements, the Doppler Shift Attenuation Method (DSAM) is the one adopted for measuring lifetimes typically in the range of few tens of fs to few ps. The technique is based on the analysis of the observed Doppler affected gamma rays emitted by the recoils in flight. The crucial component in the related analysis is the simulation of the stopping process, of the residues of interest, in the target and the backing media. This requires calculation of the corresponding stopping powers and the same has been identified as one of the principal uncertainties in the extracted lifetime in DSAM. Traditionally the method is pursued with a thin target, for production of nuclei of interest, on a thick elemental backing wherein stopping process is perceived to occur. The present work in light of it's objectives uses a setup which is in sharp variance with the conventional scenario, such as the use of a thick molecular target, which contributes both to the production of the residues as well as their subsequent slowing down. This demanded extensive developments in the analysis procedure particularly in the domain of simulating the stopping process with due incorporation of the nuances of nuclear reaction kinematics besides subjecting the molecular medium to a detailed structural characterization, routinely carried out in the domain of material science. These developments have been used to extract the level lifetimes of nuclei at the interface of the sd & pf shells such as 26Mg, 29Si, and 32P.

Characterization of cracking behavior using posttest fractographic analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, T.; Shockey, D.A.

A determination of time to initiation of stress corrosion cracking in structures and test specimens is important for performing structural failure analysis and for setting inspection intervals. Yet it is seldom possible to establish how much of a component's lifetime represents the time to initiation of fracture and how much represents postinitiation crack growth. This exploratory research project was undertaken to examine the feasibility of determining crack initiation times and crack growth rates from posttest examination of fracture surfaces of constant-extension-rate-test (CERT) specimens by using the fracture reconstruction applying surface topography analysis (FRASTA) technique. The specimens used in this studymore » were Type 304 stainless steel fractured in several boiling water reactor (BWR) aqueous environments. 2 refs., 25 figs., 2 tabs.« less

Analysis of the Seismic Performance of Isolated Buildings according to Life-Cycle Cost

PubMed Central

Dang, Yu; Han, Jian-ping; Li, Yong-tao

2015-01-01

This paper proposes an indicator of seismic performance based on life-cycle cost of a building. It is expressed as a ratio of lifetime damage loss to life-cycle cost and determines the seismic performance of isolated buildings. Major factors are considered, including uncertainty in hazard demand and structural capacity, initial costs, and expected loss during earthquakes. Thus, a high indicator value indicates poor building seismic performance. Moreover, random vibration analysis is conducted to measure structural reliability and evaluate the expected loss and life-cycle cost of isolated buildings. The expected loss of an actual, seven-story isolated hospital building is only 37% of that of a fixed-base building. Furthermore, the indicator of the structural seismic performance of the isolated building is much lower in value than that of the structural seismic performance of the fixed-base building. Therefore, isolated buildings are safer and less risky than fixed-base buildings. The indicator based on life-cycle cost assists owners and engineers in making investment decisions in consideration of structural design, construction, and expected loss. It also helps optimize the balance between building reliability and building investment. PMID:25653677

Analysis of the seismic performance of isolated buildings according to life-cycle cost.

PubMed

Dang, Yu; Han, Jian-Ping; Li, Yong-Tao

2015-01-01

This paper proposes an indicator of seismic performance based on life-cycle cost of a building. It is expressed as a ratio of lifetime damage loss to life-cycle cost and determines the seismic performance of isolated buildings. Major factors are considered, including uncertainty in hazard demand and structural capacity, initial costs, and expected loss during earthquakes. Thus, a high indicator value indicates poor building seismic performance. Moreover, random vibration analysis is conducted to measure structural reliability and evaluate the expected loss and life-cycle cost of isolated buildings. The expected loss of an actual, seven-story isolated hospital building is only 37% of that of a fixed-base building. Furthermore, the indicator of the structural seismic performance of the isolated building is much lower in value than that of the structural seismic performance of the fixed-base building. Therefore, isolated buildings are safer and less risky than fixed-base buildings. The indicator based on life-cycle cost assists owners and engineers in making investment decisions in consideration of structural design, construction, and expected loss. It also helps optimize the balance between building reliability and building investment.

Neutron lifetimes behavior analysis considering the two-region kinetic model in the IPEN/MB-01 reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonnelli, Eduardo; Diniz, Ricardo

2014-11-11

This is a complementary work about the behavior analysis of the neutron lifetimes that was developed in the IPEN/MB-01 nuclear reactor facility. The macroscopic neutron noise technique was experimentally employed using pulse mode detectors for two stages of control rods insertion, where a total of twenty levels of subcriticality have been carried out. It was also considered that the neutron reflector density was treated as an additional group of delayed neutrons, being a sophisticated approach in the two-region kinetic theoretical model.

Time-resolved fluorescence decay measurements for flowing particles

DOEpatents

Deka, C.; Steinkamp, J.A.

1999-06-01

Time-resolved fluorescence decay measurements are disclosed for flowing particles. An apparatus and method for the measurement and analysis of fluorescence for individual cells and particles in flow are described, wherein the rapid measurement capabilities of flow cytometry and the robust measurement and analysis procedures of time-domain fluorescence lifetime spectroscopy are combined. A pulse-modulated CW laser is employed for excitation of the particles. The characteristics and the repetition rate of the excitation pulses can be readily adjusted to accommodate for fluorescence decays having a wide range of lifetimes. 12 figs.

Time-resolved fluorescence decay measurements for flowing particles

DOEpatents

Deka, Chiranjit; Steinkamp, John A.

1999-01-01

Time-resolved fluorescence decay measurements for flowing particles. An apparatus and method for the measurement and analysis of fluorescence for individual cells and particles in flow are described, wherein the rapid measurement capabilities of flow cytometry and the robust measurement and analysis procedures of time-domain fluorescence lifetime spectroscopy are combined. A pulse-modulated cw laser is employed for excitation of the particles. The characteristics and the repetition rate of the excitation pulses can be readily adjusted to accommodate for fluorescence decays having a wide range of lifetimes.

System implications of aperture-shade design for the SIRTF Observatory

NASA Technical Reports Server (NTRS)

Lee, J. H.; Brooks, W. F.; Maa, S.

1987-01-01

The 1-m-aperture Space Infrared Telescope Facility (SIRTF) will operate with a sensitivity limited only by the zodiacal background. This sensitivity requirement places severe restrictions on the amount of stray light which can reach the focal plane from off-axis sources such as the sun or earth limb. In addition, radiation from these sources can degrade the lifetime of the telescope and instrument cryogenic system which is now planned for two years before the first servicing. Since the aperture of the telescope represents a break in the telescope insulation system and is effectively the first element in the optical train, the aperture shade is a key system component. The mass, length, and temperature of the shade should be minimized to reduce system cost while maximizing the telescope lifetime and stray light performance. The independent geometric parameters that characterize an asymmetrical shade for a 600 km, 28 deg orbit were identified, and the system sensitivity to the three most important shade parameters were explored. Despite the higher heat loads compared to previously studied polar orbit missions, the analysis determined that passive radiators of a reasonable size are sufficient to meet the system requirements. An optimized design for the SIRTF mission, based on the sensitivity analysis, is proposed.

EqualWrites: Reducing Intra-set Write Variations for Enhancing Lifetime of Non-volatile Caches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mittal, Sparsh; Vetter, Jeffrey S.

Driven by the trends of increasing core-count and bandwidth-wall problem, the size of last level caches (LLCs) has greatly increased and hence, the researchers have explored non-volatile memories (NVMs) which provide high density and consume low-leakage power. Since NVMs have low write-endurance and the existing cache management policies are write variation-unaware, effective wear-leveling techniques are required for achieving reasonable cache lifetimes using NVMs. We present EqualWrites, a technique for mitigating intra-set write variation. In this paper, our technique works by recording the number of writes on a block and changing the cache-block location of a hot data-item to redirect themore » future writes to a cold block to achieve wear-leveling. Simulation experiments have been performed using an x86-64 simulator and benchmarks from SPEC06 and HPC (high-performance computing) field. The results show that for single, dual and quad-core system configurations, EqualWrites improves cache lifetime by 6.31X, 8.74X and 10.54X, respectively. In addition, its implementation overhead is very small and it provides larger improvement in lifetime than three other intra-set wear-leveling techniques and a cache replacement policy.« less

EqualWrites: Reducing Intra-set Write Variations for Enhancing Lifetime of Non-volatile Caches

DOE PAGES

Mittal, Sparsh; Vetter, Jeffrey S.

2015-01-29

Driven by the trends of increasing core-count and bandwidth-wall problem, the size of last level caches (LLCs) has greatly increased and hence, the researchers have explored non-volatile memories (NVMs) which provide high density and consume low-leakage power. Since NVMs have low write-endurance and the existing cache management policies are write variation-unaware, effective wear-leveling techniques are required for achieving reasonable cache lifetimes using NVMs. We present EqualWrites, a technique for mitigating intra-set write variation. In this paper, our technique works by recording the number of writes on a block and changing the cache-block location of a hot data-item to redirect themore » future writes to a cold block to achieve wear-leveling. Simulation experiments have been performed using an x86-64 simulator and benchmarks from SPEC06 and HPC (high-performance computing) field. The results show that for single, dual and quad-core system configurations, EqualWrites improves cache lifetime by 6.31X, 8.74X and 10.54X, respectively. In addition, its implementation overhead is very small and it provides larger improvement in lifetime than three other intra-set wear-leveling techniques and a cache replacement policy.« less

Life Cycle analysis data and results for geothermal and other electricity generation technologies

DOE Data Explorer

Sullivan, John

2013-06-04

Life cycle analysis (LCA) is an environmental assessment method that quantifies the environmental performance of a product system over its entire lifetime, from cradle to grave. Based on a set of relevant metrics, the method is aptly suited for comparing the environmental performance of competing products systems. This file contains LCA data and results for electric power production including geothermal power. The LCA for electric power has been broken down into two life cycle stages, namely plant and fuel cycles. Relevant metrics include the energy ratio and greenhouse gas (GHG) ratios, where the former is the ratio of system input energy to total lifetime electrical energy out and the latter is the ratio of the sum of all incurred greenhouse gases (in CO2 equivalents) divided by the same energy output. Specific information included herein are material to power (MPR) ratios for a range of power technologies for conventional thermoelectric, renewables (including three geothermal power technologies), and coproduced natural gas/geothermal power. For the geothermal power scenarios, the MPRs include the casing, cement, diesel, and water requirements for drilling wells and topside piping. Also included herein are energy and GHG ratios for plant and fuel cycle stages for the range of considered electricity generating technologies. Some of this information are MPR data extracted directly from the literature or from models (eg. ICARUS – a subset of ASPEN models) and others (energy and GHG ratios) are results calculated using GREET models and MPR data. MPR data for wells included herein were based on the Argonne well materials model and GETEM well count results.

Fluorescence decay data analysis correcting for detector pulse pile-up at very high count rates

NASA Astrophysics Data System (ADS)

Patting, Matthias; Reisch, Paja; Sackrow, Marcus; Dowler, Rhys; Koenig, Marcelle; Wahl, Michael

2018-03-01

Using time-correlated single photon counting for the purpose of fluorescence lifetime measurements is usually limited in speed due to pile-up. With modern instrumentation, this limitation can be lifted significantly, but some artifacts due to frequent merging of closely spaced detector pulses (detector pulse pile-up) remain an issue to be addressed. We propose a data analysis method correcting for this type of artifact and the resulting systematic errors. It physically models the photon losses due to detector pulse pile-up and incorporates the loss in the decay fit model employed to obtain fluorescence lifetimes and relative amplitudes of the decay components. Comparison of results with and without this correction shows a significant reduction of systematic errors at count rates approaching the excitation rate. This allows quantitatively accurate fluorescence lifetime imaging at very high frame rates.

Fuel-Flexible Gasification-Combustion Technology for Production of H2 and Sequestration-Ready CO2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parag Kulkarni; Jie Guan; Raul Subia

In the near future, the nation will continue to rely on fossil fuels for electricity, transportation, and chemicals. It is necessary to improve both the process efficiency and environmental impact of fossil fuel utilization including greenhouse gas management. GE Global Research (GEGR) investigated an innovative fuel-flexible Unmixed Fuel Processor (UFP) technology with potential to produce H{sub 2}, power, and sequestration-ready CO{sub 2} from coal and other solid fuels. The UFP technology offers the long-term potential for reduced cost, increased process efficiency relative to conventional gasification and combustion systems, and near-zero pollutant emissions. GE was awarded a contract from U.S. DOEmore » NETL to investigate and develop the UFP technology. Work started on the Phase I program in October 2000 and on the Phase II effort in April 2005. In the UFP technology, coal, water and air are simultaneously converted into (1) hydrogen rich stream that can be utilized in fuel cells or turbines, (2) CO{sub 2} rich stream for sequestration, and (3) high temperature/pressure vitiated air stream to produce electricity in a gas turbine expander. The process produces near-zero emissions with an estimated efficiency higher than Integrated Gasification Combined Cycle (IGCC) process with conventional CO{sub 2} separation. The Phase I R&D program established the chemical feasibility of the major reactions of the integrated UFP technology through lab-, bench- and pilot-scale testing. A risk analysis session was carried out at the end of Phase I effort to identify the major risks in the UFP technology and a plan was developed to mitigate these risks in the Phase II of the program. The Phase II effort focused on three high-risk areas: economics, lifetime of solids used in the UFP process, and product gas quality for turbines (or the impact of impurities in the coal on the overall system). The economic analysis included estimating the capital cost as well as the costs of hydrogen and electricity for a full-scale UFP plant. These costs were benchmarked with IGCC polygen plants with similar level of CO{sub 2} capture. Based on the promising economic analysis comparison results (performed with the help from Worley Parsons), GE recommended a 'Go' decision in April 2006 to continue the experimental investigation of the UFP technology to address the remaining risks i.e. solids lifetime and the impact of impurities in the coal on overall system. Solids attrition and lifetime risk was addressed via bench-scale experiments that monitor solids performance over time and by assessing materials interactions at operating conditions. The product gas under the third reactor (high-temperature vitiated air) operating conditions was evaluated to assess the concentration of particulates, pollutants and other impurities relative to the specifications required for gas turbine feed streams. During this investigation, agglomeration of solids used in the UFP process was identified as a serious risk that impacts the lifetime of the solids and in turn feasibility of the UFP technology. The main causes of the solids agglomeration were the combination of oxygen transfer material (OTM) reduction at temperatures {approx}1000 C and interaction between OTM and CO{sub 2} absorbing material (CAM) at high operating temperatures (>1200 C). At the end of phase II, in March 2008, GEGR recommended a 'No-go' decision for taking the UFP technology to the next level of development, i.e. development of a 3-5 MW prototype system, at this time. GEGR further recommended focused materials development research programs on improving the performance and lifetime of solids materials used in UFP or chemical looping technologies. The scale-up activities would be recommended only after mitigating the risks involved with the agglomeration and overall lifetime of the solids. This is the final report for the phase II of the DOE-funded Vision 21 program entitled 'Fuel-Flexible Gasification-Combustion Technology for Production of H{sub 2} and Sequestration-Ready CO{sub 2}' (DOE Award No. DE-FC26-00NT40974). The report focuses on the major accomplishments and lessons learned in analyzing the risks of the novel UFP technology during Phase II of the DOE program.« less

Scout: An Impact Analysis Tool for Building Energy-Efficiency Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Chioke; Langevin, Jared; Roth, Amir

Evaluating the national impacts of candidate U.S. building energy-efficiency technologies has historically been difficult for organizations with large energy efficiency portfolios. In particular, normalizing results from technology-specific impact studies is time-consuming when those studies do not use comparable assumptions about the underlying building stock. To equitably evaluate its technology research, development, and deployment portfolio, the U.S. Department of Energy's Building Technologies Office has developed Scout, a software tool that quantitatively assesses the energy and CO2 impacts of building energy-efficiency measures on the national building stock. Scout efficiency measures improve upon the unit performance and/or lifetime operational costs of an equipmentmore » stock baseline that is determined from the U.S. Energy Information Administration Annual Energy Outlook (AEO). Scout measures are characterized by a market entry and exit year, unit performance level, cost, and lifetime. To evaluate measures on a consistent basis, Scout uses EnergyPlus simulation on prototype building models to translate measure performance specifications to whole-building energy savings; these savings impacts are then extended to a national scale using floor area weighting factors. Scout represents evolution in the building stock over time using AEO projections for new construction, retrofit, and equipment replacements, and competes technologies within market segments under multiple adoption scenarios. Scout and its efficiency measures are open-source, as is the EnergyPlus whole building simulation framework that is used to evaluate measure performance. The program is currently under active development and will be formally released once an initial set of measures has been analyzed and reviewed.« less

Phasor-based single-molecule fluorescence lifetime imaging using a wide-field photon-counting detector

PubMed Central

Colyer, R.; Siegmund, O.; Tremsin, A.; Vallerga, J.; Weiss, S.; Michalet, X.

2011-01-01

Fluorescence lifetime imaging (FLIM) is a powerful approach to studying the immediate environment of molecules. For example, it is used in biology to study changes in the chemical environment, or to study binding processes, aggregation, and conformational changes by measuring Förster resonance energy transfer (FRET) between donor and acceptor fluorophores. FLIM can be acquired by time-domain measurements (time-correlated single-photon counting) or frequency-domain measurements (with PMT modulation or digital frequency domain acquisition) in a confocal setup, or with wide-field systems (using time-gated cameras). In the best cases, the resulting data is analyzed in terms of multicomponent fluorescence lifetime decays with demanding requirements in terms of signal level (and therefore limited frame rate). Recently, the phasor approach has been proposed as a powerful alternative for fluorescence lifetime analysis of FLIM, ensemble, and single-molecule experiments. Here we discuss the advantages of combining phasor analysis with a new type of FLIM acquisition hardware presented previously, consisting of a high temporal and spatial resolution wide-field single-photon counting device (the H33D detector). Experimental data with live cells and quantum dots will be presented as an illustration of this new approach. PMID:21625298

Beyond ‘MSM’: Sexual Desire Among Bisexually-Active Latino Men in New York City

PubMed Central

Muñoz-Laboy, Miguel A.

2015-01-01

Latino male bisexuality has been studied for the most part with a focus on men who have sex with men (MSM) and with little attention to sexual desire. The goal of this article is to present a comprehensive understanding of how sexual desire is organized, enacted through sexual activity, and interpreted in the sexual lives of bisexually-active Latino men. To achieve this aim, an analysis was made of 18 sexual histories of bisexually active Latino men who participated in a two-year ethnographic study. Four configurations of sexual desire were constructed to reflect what was found in this population of bisexually-active Latino men: (a) lifetime homoerotic desire and casual sex with women; (b) lifetime heteroerotic desire, but commercial sex with men; (c) lifetime heteroerotic/transgender desire; (d) lifetime sexual desire for women and men. These configurations are explored in detail in this article. The analysis presented here is intended to offer insights into the overall study of Latino male bisexuality and into the foundations for the design of HIV and STI prevention programs directed toward bisexually-active Latino men and their partners. PMID:26412977

Anorexia Nervosa: Analysis of Trabecular Texture with CT

PubMed Central

Tabari, Azadeh; Torriani, Martin; Miller, Karen K.; Klibanski, Anne; Kalra, Mannudeep K.

2017-01-01

Purpose To determine indexes of skeletal integrity by using computed tomographic (CT) trabecular texture analysis of the lumbar spine in patients with anorexia nervosa and normal-weight control subjects and to determine body composition predictors of trabecular texture. Materials and Methods This cross-sectional study was approved by the institutional review board and compliant with HIPAA. Written informed consent was obtained. The study included 30 women with anorexia nervosa (mean age ± standard deviation, 26 years ± 6) and 30 normal-weight age-matched women (control group). All participants underwent low-dose single-section quantitative CT of the L4 vertebral body with use of a calibration phantom. Trabecular texture analysis was performed by using software. Skewness (asymmetry of gray-level pixel distribution), kurtosis (pointiness of pixel distribution), entropy (inhomogeneity of pixel distribution), and mean value of positive pixels (MPP) were assessed. Bone mineral density and abdominal fat and paraspinal muscle areas were quantified with quantitative CT. Women with anorexia nervosa and normal-weight control subjects were compared by using the Student t test. Linear regression analyses were performed to determine associations between trabecular texture and body composition. Results Women with anorexia nervosa had higher skewness and kurtosis, lower MPP (P < .001), and a trend toward lower entropy (P = .07) compared with control subjects. Bone mineral density, abdominal fat area, and paraspinal muscle area were inversely associated with skewness and kurtosis and positively associated with MPP and entropy. Texture parameters, but not bone mineral density, were associated with lowest lifetime weight and duration of amenorrhea in anorexia nervosa. Conclusion Patients with anorexia nervosa had increased skewness and kurtosis and decreased entropy and MPP compared with normal-weight control subjects. These parameters were associated with lowest lifetime weight and duration of amenorrhea, but there were no such associations with bone mineral density. These findings suggest that trabecular texture analysis might contribute information about bone health in anorexia nervosa that is independent of that provided with bone mineral density. © RSNA, 2016 PMID:27797678

Anorexia Nervosa: Analysis of Trabecular Texture with CT.

PubMed

Tabari, Azadeh; Torriani, Martin; Miller, Karen K; Klibanski, Anne; Kalra, Mannudeep K; Bredella, Miriam A

2017-04-01

Purpose To determine indexes of skeletal integrity by using computed tomographic (CT) trabecular texture analysis of the lumbar spine in patients with anorexia nervosa and normal-weight control subjects and to determine body composition predictors of trabecular texture. Materials and Methods This cross-sectional study was approved by the institutional review board and compliant with HIPAA. Written informed consent was obtained. The study included 30 women with anorexia nervosa (mean age ± standard deviation, 26 years ± 6) and 30 normal-weight age-matched women (control group). All participants underwent low-dose single-section quantitative CT of the L4 vertebral body with use of a calibration phantom. Trabecular texture analysis was performed by using software. Skewness (asymmetry of gray-level pixel distribution), kurtosis (pointiness of pixel distribution), entropy (inhomogeneity of pixel distribution), and mean value of positive pixels (MPP) were assessed. Bone mineral density and abdominal fat and paraspinal muscle areas were quantified with quantitative CT. Women with anorexia nervosa and normal-weight control subjects were compared by using the Student t test. Linear regression analyses were performed to determine associations between trabecular texture and body composition. Results Women with anorexia nervosa had higher skewness and kurtosis, lower MPP (P < .001), and a trend toward lower entropy (P = .07) compared with control subjects. Bone mineral density, abdominal fat area, and paraspinal muscle area were inversely associated with skewness and kurtosis and positively associated with MPP and entropy. Texture parameters, but not bone mineral density, were associated with lowest lifetime weight and duration of amenorrhea in anorexia nervosa. Conclusion Patients with anorexia nervosa had increased skewness and kurtosis and decreased entropy and MPP compared with normal-weight control subjects. These parameters were associated with lowest lifetime weight and duration of amenorrhea, but there were no such associations with bone mineral density. These findings suggest that trabecular texture analysis might contribute information about bone health in anorexia nervosa that is independent of that provided with bone mineral density. © RSNA, 2016.

Chlorophyll fluorescence lifetime imaging provides new insight into the chlorosis induced by plant virus infection.

PubMed

Lei, Rong; Jiang, Hongshan; Hu, Fan; Yan, Jin; Zhu, Shuifang

2017-02-01

Leaf chlorosis induced by plant virus infection has a short fluorescence lifetime, which reflects damaged photosynthetic complexes and degraded chloroplasts. Plant viruses often induce chlorosis and necrosis, which are intimately related to photosynthetic functions. Chlorophyll fluorescence lifetime measurement is a valuable noninvasive tool for analyzing photosynthetic processes and is a sensitive indicator of the environment surrounding the fluorescent molecules. In this study, our central goal was to explore the effect of viral infection on photosynthesis by employing chlorophyll fluorescence lifetime imaging (FLIM), steady-state fluorescence, non-photochemical quenching (NPQ), transmission electron microscopy (TEM), and pigment analysis. The data indicated that the chlorophyll fluorescence lifetime of chlorotic leaves was significantly shorter than that of healthy control leaves, and the fitted short lifetime component of chlorophyll fluorescence of chlorotic leaves was dominant. This dominant short lifetime component may result from damage to the structure of thylakoid, which was confirmed by TEM. The NPQ value of chlorotic leaves was slightly higher than that of healthy green leaves, which can be explained by increased neoxanthin, lutein and violaxanthin content relative to chlorophyll a. The difference in NPQ is slight, but FLIM can provide simple and direct characterization of PSII structure and photosynthetic function. Therefore, this technique shows great potential as a simple and rapid method for studying mechanisms of plant virus infection.

A 20000-hour endurance test of a structurally and thermally integrated 5-cm diameter ion thruster main cathode

NASA Technical Reports Server (NTRS)

Wintucky, E. G.

1975-01-01

A 5-cm diameter mercury ion thruster main cathode has completed over 20,000 hours of operation in an ongoing lifetime endurance test. The cathode operating parameters remained at acceptable performance levels throughout the test, the first 9175 hours of which were part of a thruster endurance test. After 20,000 hours, the cathode discharge was easily restarted, the tip orifice indicated negligible erosion and the tip heater showed no degradation. The cathode-isolator- vaporizer assembly, a major thruster subsystem, has thus successfully demonstrated an operational lifetime capability of 20,000 hours, which is the lifetime goal of the 8-cm diameter auxiliary propulsion ion thruster.

Lifetimes of relativistic heavy-ion beams in the High Energy Storage Ring of FAIR

NASA Astrophysics Data System (ADS)

Shevelko, V. P.; Litvinov, Yu. A.; Stöhlker, Th.; Tolstikhina, I. Yu.

2018-04-01

The High Energy Storage Ring, HESR, will be constructed at the Facility for Antiproton and Ion Research, FAIR, Darmstadt. For the first time, it will be possible to perform experiments with cooled high-intensity stable and radioactive heavy ions at highly relativistic energies. To design experiments at the HESR, realistic estimations of beam lifetimes are indispensable. Here we report calculated cross sections and lifetimes for typical U88+ , U90+ , U92+ , Sn49+ and Sn50+ ions in the energy range E = 400 MeV/u-5 GeV/u, relevant for the HESR. Interactions with the residual gas and with internal gas-jet targets are also considered.

Low-lying electromagnetic transition strengths in 180Pt

NASA Astrophysics Data System (ADS)

Müller-Gatermann, C.; Dewald, A.; Fransen, C.; Braunroth, T.; Jolie, J.; Litzinger, J.; Régis, J. M.; von Spee, F.; Warr, N.; Zell, K. O.; Grahn, T.; Greenlees, P. T.; Hauschild, K.; Jakobsson, U.; Julin, R.; Juutinen, S.; Ketelhut, S.; Nieminen, P.; Nyman, M.; Peura, P.; Rahkila, P.; Ruotsalainen, P.; Sandzelius, M.; Sarén, J.; Scholey, C.; Sorri, J.; Stolze, S.; Uusitalo, J.; Petkov, P.

2018-02-01

Lifetime measurements have been performed using the 98Mo(86Kr,4 n )180Pt reaction at a beam energy of 380 MeV, and the recoil distance Doppler-shift method. In a second experiment the 168Yb(16O,4 n )180Pt reaction at a beam energy of 88 MeV using the Ge-gated γ -γ fast timing technique was used to determine lifetimes. Lifetimes of the four lowest yrast states of 180Pt have been determined. The experimental data are compared to calculations within the framework of the interacting boson model and the general collective model. Both models predict a deformed ground state and are consistent with all the remaining experimental results.

A current-assisted CMOS photonic sampler with two taps for fluorescence lifetime sensing

NASA Astrophysics Data System (ADS)

Ingelberts, H.; Kuijk, M.

2016-04-01

Imaging based on fluorescence lifetime is becoming increasingly important in medical and biological applications. State-of- the-art fluorescence lifetime microscopes either use bulky and expensive gated image intensifiers coupled to a CCD or single-photon detectors in a slow scanning setup. Numerous attempts are being made to create compact, cost-effective all- CMOS imagers for fluorescence lifetime sensing. Single-photon avalanche diode (SPAD) imagers can have very good timing resolution and noise characteristics but have low detection efficiency. Another approach is to use CMOS imagers based on demodulation detectors. These imagers can be either very fast or very efficient but it remains a challenge to combine both characteristics. Recently we developed the current-assisted photonic sampler (CAPS) to tackle these problems and in this work, we present a new CAPS with two detection taps that can sample a fluorescence decay in two time windows. In the case of mono-exponential decays, two windows provide enough information to resolve the lifetime. We built an electro-optical setup to characterize the detector and use it for fluorescence lifetime measurements. It consists of a supercontinuum pulsed laser source, an optical system to focus light into the detector and picosecond timing electronics. We describe the structure and operation of the two-tap CAPS and provide basic characterization of the speed performance at multiple wavelengths in the visible and near-infrared spectrum. We also record fluorescence decays of different visible and NIR fluorescent dyes and provide different methods to resolve the fluorescence lifetime.

Level Lifetime Measurements in ^150Sm

NASA Astrophysics Data System (ADS)

Barton, C. J.; Krücken, R.; Beausang, C. W.; Caprio, M. A.; Casten, R. F.; Cooper, J. R.; Hecht, A. A.; Newman, H.; Novak, J. R.; Pietralla, N.; Wolf, A.; Zyromski, K. E.; Zamfir, N. V.; Börner, H. G.

2000-10-01

Shape/phase coexistence and the evolution of structure in the region around ^152Sm have recently been of great interest. Experiments performed at WNSL, Yale University, measured the lifetime of low spin states in a target of ^150Sm with the recoil distance method (RDM) and the Doppler-shift attenuation method (DSAM). The low spin states, both yrast and non-yrast, were populated via Coulomb excitation with a beam of ^16O. The experiments were performed with the NYPD plunger in conjunction with the SPEEDY γ-ray array. The SCARY array of solar cells was used to detect backward scattered projectiles, selecting forward flying Coulomb excited target nuclei. The measured lifetimes yield, for example, B(E2) values for transitions such as the 2^+2 arrow 2^+1 and the 2^+3 arrow 0^+_1. Data from the RDM measurment and the DSAM experiment will be presented. This work was supported by the US DOE under grants DE-FG02-91ER-40609 and DE-FG02-88ER-40417.

InAs/GaSb type-II superlattices versus HgCdTe ternary alloys: future prospect

NASA Astrophysics Data System (ADS)

Rogalski, A.

2017-10-01

InAs/GaSb T2SL photodetectors offer similar performance to HgCdTe at an equivalent cutoff wavelength, but with a sizeable penalty in operating temperature, due to the inherent difference in Shockley-Read lifetimes. It is predicted that since the future IR systems will be based on the room temperature operation of depletion-current limited arrays with pixel densities that are fully consistent with background- and diffraction-limited performance due to the system optics, the material system with long Shockley-Read lifetime will be required. Since T2SLs are much resisted in attempts to improve its SR lifetime, currently the only material that meets this requirement is HgCdTe. Due to less ionic chemical bonding, III-V semiconductors are more robust than their II-VI counterparts. As a result, III-V-based FPAs excel in operability, spatial uniformity, temporal stability, scalability, producibility, and affordability - the so-called "ibility" advantages.

Predicting the breakdown strength and lifetime of nanocomposites using a multi-scale modeling approach

NASA Astrophysics Data System (ADS)

Huang, Yanhui; Zhao, He; Wang, Yixing; Ratcliff, Tyree; Breneman, Curt; Brinson, L. Catherine; Chen, Wei; Schadler, Linda S.

2017-08-01

It has been found that doping dielectric polymers with a small amount of nanofiller or molecular additive can stabilize the material under a high field and lead to increased breakdown strength and lifetime. Choosing appropriate fillers is critical to optimizing the material performance, but current research largely relies on experimental trial and error. The employment of computer simulations for nanodielectric design is rarely reported. In this work, we propose a multi-scale modeling approach that employs ab initio, Monte Carlo, and continuum scales to predict the breakdown strength and lifetime of polymer nanocomposites based on the charge trapping effect of the nanofillers. The charge transfer, charge energy relaxation, and space charge effects are modeled in respective hierarchical scales by distinctive simulation techniques, and these models are connected together for high fidelity and robustness. The preliminary results show good agreement with the experimental data, suggesting its promise for use in the computer aided material design of high performance dielectrics.

Reliability and performance experience with flat-plate photovoltaic modules

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1982-01-01

Statistical models developed to define the most likely sources of photovoltaic (PV) array failures and the optimum method of allowing for the defects in order to achieve a 20 yr lifetime with acceptable performance degradation are summarized. Significant parameters were the cost of energy, annual power output, initial cost, replacement cost, rate of module replacement, the discount rate, and the plant lifetime. Acceptable degradation allocations were calculated to be 0.0001 cell failures/yr, 0.005 module failures/yr, 0.05 power loss/yr, a 0.01 rate of power loss/yr, and a 25 yr module wear-out length. Circuit redundancy techniques were determined to offset cell failures using fault tolerant designs such as series/parallel and bypass diode arrangements. Screening processes have been devised to eliminate cells that will crack in operation, and multiple electrical contacts at each cell compensate for the cells which escape the screening test and then crack when installed. The 20 yr array lifetime is expected to be achieved in the near-term.

Low-frequency wide-field fluorescence lifetime imaging using a high-power near-infrared light-emitting diode light source

PubMed Central

Gioux, Sylvain; Lomnes, Stephen J.; Choi, Hak Soo; Frangioni, John V.

2010-01-01

Fluorescence lifetime imaging (FLi) could potentially improve exogenous near-infrared (NIR) fluorescence imaging, because it offers the capability of discriminating a signal of interest from background, provides real-time monitoring of a chemical environment, and permits the use of several different fluorescent dyes having the same emission wavelength. We present a high-power, LED-based, NIR light source for the clinical translation of wide-field (larger than 5 cm in diameter) FLi at frequencies up to 35 MHz. Lifetime imaging of indocyanine green (ICG), IRDye 800-CW, and 3,3′-diethylthiatricarbocyanine iodide (DTTCI) was performed over a large field of view (10 cm by 7.5 cm) using the LED light source. For comparison, a laser diode light source was employed as a gold standard. Experiments were performed both on the bench by diluting the fluorescent dyes in various chemical environments in Eppendorf tubes, and in vivo by injecting the fluorescent dyes mixed in Matrigel subcutaneously into CD-1 mice. Last, measured fluorescence lifetimes obtained using the LED and the laser diode sources were compared with those obtained using a state-of-the-art time-domain imaging system and with those previously described in the literature. On average, lifetime values obtained using the LED and the laser diode light sources were consistent, exhibiting a mean difference of 3% from the expected values and a coefficient of variation of 12%. Taken together, our study offers an alternative to laser diodes for clinical translation of FLi and explores the use of relatively low frequency modulation for in vivo imaging. PMID:20459250

Estimation of lifetime distributions on 1550-nm DFB laser diodes using Monte-Carlo statistic computations

NASA Astrophysics Data System (ADS)

Deshayes, Yannick; Verdier, Frederic; Bechou, Laurent; Tregon, Bernard; Danto, Yves; Laffitte, Dominique; Goudard, Jean Luc

2004-09-01

High performance and high reliability are two of the most important goals driving the penetration of optical transmission into telecommunication systems ranging from 880 nm to 1550 nm. Lifetime prediction defined as the time at which a parameter reaches its maximum acceptable shirt still stays the main result in terms of reliability estimation for a technology. For optoelectronic emissive components, selection tests and life testing are specifically used for reliability evaluation according to Telcordia GR-468 CORE requirements. This approach is based on extrapolation of degradation laws, based on physics of failure and electrical or optical parameters, allowing both strong test time reduction and long-term reliability prediction. Unfortunately, in the case of mature technology, there is a growing complexity to calculate average lifetime and failure rates (FITs) using ageing tests in particular due to extremely low failure rates. For present laser diode technologies, time to failure tend to be 106 hours aged under typical conditions (Popt=10 mW and T=80°C). These ageing tests must be performed on more than 100 components aged during 10000 hours mixing different temperatures and drive current conditions conducting to acceleration factors above 300-400. These conditions are high-cost, time consuming and cannot give a complete distribution of times to failure. A new approach consists in use statistic computations to extrapolate lifetime distribution and failure rates in operating conditions from physical parameters of experimental degradation laws. In this paper, Distributed Feedback single mode laser diodes (DFB-LD) used for 1550 nm telecommunication network working at 2.5 Gbit/s transfer rate are studied. Electrical and optical parameters have been measured before and after ageing tests, performed at constant current, according to Telcordia GR-468 requirements. Cumulative failure rates and lifetime distributions are computed using statistic calculations and equations of drift mechanisms versus time fitted from experimental measurements.

Method for Aluminum Oxide Thin Films Prepared through Low Temperature Atomic Layer Deposition for Encapsulating Organic Electroluminescent Devices

PubMed Central

Li, Hui-Ying; Liu, Yun-Fei; Duan, Yu; Yang, Yong-Qiang; Lu, Yi-Nan

2015-01-01

Preparation of dense alumina (Al2O3) thin film through atomic layer deposition (ALD) provides a pathway to achieve the encapsulation of organic light emitting devices (OLED). Unlike traditional ALD which is usually executed at higher reaction n temperatures that may affect the performance of OLED, this application discusses the development on preparation of ALD thin film at a low temperature. One concern of ALD is the suppressing effect of ambient temperature on uniformity of thin film. To mitigate this issue, the pumping time in each reaction cycle was increased during the preparation process, which removed reaction byproducts and inhibited the formation of vacancies. As a result, the obtained thin film had both high uniformity and density properties, which provided an excellent encapsulation performance. The results from microstructure morphology analysis, water vapor transmission rate, and lifetime test showed that the difference in uniformity between thin films prepared at low temperatures, with increased pumping time, and high temperatures was small and there was no obvious influence of increased pumping time on light emitting performance. Meanwhile, the permeability for water vapor of the thin film prepared at a low temperature was found to reach as low as 1.5 × 10−4 g/(m2·day) under ambient conditions of 25 °C and 60% relative humidity, indicating a potential extension in the lifetime for the OLED. PMID:28787960

FDTD and transfer matrix methods for evaluating the performance of photonic crystal based microcavities for exciton-polaritons

NASA Astrophysics Data System (ADS)

Liu, Yi-Cheng; Byrnes, Tim

2016-11-01

We investigate alternative microcavity structures for exciton-polaritons consisting of photonic crystals instead of distributed Bragg reflectors. Finite-difference time-domain simulations and scattering transfer matrix methods are used to evaluate the cavity performance. The results are compared with conventional distributed Bragg reflectors. We find that in terms of the photon lifetime, the photonic crystal based microcavities are competitive, with typical lifetimes in the region of ∼20 ps being achieved. The photonic crystal microcavities have the advantage that they are compact and are frequency adjustable, showing that they are viable to investigate exciton-polariton condensation physics.

Active matrix organic light emitting diode (AMOLED)-XL performance and life test results

NASA Astrophysics Data System (ADS)

Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Draper, Russell S.; Lum, Alden K.; Ghosh, Amalkumar P.; Prache, Olivier; Wacyk, Ihor

2009-05-01

The US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. RDECOM CERDEC NVESD conducted life tests on these displays, finding over 200% lifetime improvement for the OLED-XL devices over the standard OLED displays, publishing results at the 2007 and 2008 SPIE Defense and Security Symposia1,2. In 2008, eMagin Corporation made additional improvements on the lifetime of their displays and developed the first SXGA (1280 × 1024 triad pixels) OLED microdisplay. A summary of the life and performance tests run at CERDEC NVESD will be presented along with a recap of previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems: where good fits are made, and where further development might be desirable.

Molecular engineering to improve carrier lifetimes for organic photovoltaic devices with thick active layers

DOE PAGES

Oosterhout, Stefan D.; Braunecker, Wade A.; Owczarczyk, Zbyslaw R.; ...

2017-04-27

The morphology of the bulk heterojunction absorber layer in an organic photovoltaic (OPV) device has a profound effect on the electrical properties and efficiency of the device. Previous work has consistently demonstrated that the solubilizing side-chains of the donor material affect these properties and device performance in a non-trivial way. Here, using Time-Resolved Microwave Conductivity (TRMC), we show by direct measurements of carrier lifetimes that the choice of side chains can also make a substantial difference in photocarrier dynamics. We have previously demonstrated a correlation between peak photoconductance measured by TRMC and device efficiencies; here, we demonstrate that TRMC photocarriermore » dynamics have an important bearing on device performance in a case study of devices made from donor materials with linear vs. branched side-chains and with variable active layer thicknesses. We use Grazing-Incidence Wide Angle X-ray Scattering to elucidate the cause of the different carrier lifetimes as a function of different aggregation behavior in the polymers. Consequently, the results help establish TRMC as a technique for screening OPV donor materials whose devices maintain performance in thick active layers (>250 nm) designed to improve light harvesting, film reproducibility, and ease of processing.« less

Effects of surface passivation on twin-free GaAs nanosheets.

PubMed

Arab, Shermin; Chi, Chun-Yung; Shi, Teng; Wang, Yuda; Dapkus, Daniel P; Jackson, Howard E; Smith, Leigh M; Cronin, Stephen B

2015-02-24

Unlike nanowires, GaAs nanosheets exhibit no twin defects, stacking faults, or dislocations even when grown on lattice mismatched substrates. As such, they are excellent candidates for optoelectronic applications, including LEDs and solar cells. We report substantial enhancements in the photoluminescence efficiency and the lifetime of passivated GaAs nanosheets produced using the selected area growth (SAG) method with metal organic chemical vapor deposition (MOCVD). Measurements are performed on individual GaAs nanosheets with and without an AlGaAs passivation layer. Both steady-state photoluminescence and time-resolved photoluminescence spectroscopy are performed to study the optoelectronic performance of these nanostructures. Our results show that AlGaAs passivation of GaAs nanosheets leads to a 30- to 40-fold enhancement in the photoluminescence intensity. The photoluminescence lifetime increases from less than 30 to 300 ps with passivation, indicating an order of magnitude improvement in the minority carrier lifetime. We attribute these enhancements to the reduction of nonradiative recombination due to the compensation of surface states after passivation. The surface recombination velocity decreases from an initial value of 2.5 × 10(5) to 2.7 × 10(4) cm/s with passivation.

Unattended Sensor System With CLYC Detectors

NASA Astrophysics Data System (ADS)

Myjak, Mitchell J.; Becker, Eric M.; Gilbert, Andrew J.; Hoff, Jonathan E.; Knudson, Christa K.; Landgren, Peter C.; Lee, Samantha F.; McDonald, Benjamin S.; Pfund, David M.; Redding, Rebecca L.; Smart, John E.; Taubman, Matthew S.; Torres-Torres, Carlos R.; Wiseman, Clinton G.

2016-06-01

We have developed an unattended sensor for detecting anomalous radiation sources. The system combines several technologies to reduce size and weight, increase battery lifetime, and improve decision-making capabilities. Sixteen Cs2LiYCl6:Ce (CLYC) scintillators allow for gamma-ray spectroscopy and neutron detection in the same volume. Low-power electronics for readout, high voltage bias, and digital processing reduce the total operating power to 1.7 W. Computationally efficient analysis algorithms perform spectral anomaly detection and isotope identification. When an alarm occurs, the system transmits alarm information over a cellular modem. In this paper, we describe the overall design of the unattended sensor, present characterization results, and compare the performance to stock NaI:Tl and 3He detectors.

Unattended Sensor System With CLYC Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myjak, Mitchell J.; Becker, Eric M.; Gilbert, Andrew J.

2016-06-01

We have developed a next-generation unattended sensor for detecting anomalous radiation sources. The system combines several technologies to reduce size and weight, increase battery lifetime, and improve decision-making capabilities. Sixteen Cs2LiYCl6:Ce (CLYC) scintillators allow for gamma-ray spectroscopy and neutron detection in the same volume. Low-power electronics for readout, high voltage bias, and digital processing reduce the total operating power to 1.3 W. Computationally efficient analysis algorithms perform spectral anomaly detection and isotope identification. When an alarm occurs, the system transmits alarm information over a cellular modem. In this paper, we describe the overall design of the unattended sensor, present characterizationmore » results, and compare the performance to stock NaI:Tl and 3He detectors.« less

A Measurement of the D+(s) lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Link, J.M.; Yager, P.M.; /UC, Davis

2005-04-01

A high statistics measurement of the D{sub s}{sup +} lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. They describe the analysis of the two decay modes, D{sub s}{sup +} {yields} {phi}(1020){pi}{sup +} and D{sub s}{sup +} {yields} {bar K}*(892){sup 0}K{sup +}, used for the measurement. The measured lifetime is 507.4 {+-} 5.5(stat.) {+-} 5.1(syst.) is using 8961 {+-} 105 D{sub s}{sup +} {yields} {phi}(1020){pi}{sup +} and 4680 {+-} 90 D{sub s}{sup +} {yields} {bar K}*(892){sup 0} K{sup +} decays. This is a significant improvement over the present world average.

International Space Station Major Constituent Analyzer On-Orbit Performance

NASA Technical Reports Server (NTRS)

Gardner, Ben D.; Erwin, Philip M.; Thoresen, Souzan; Granahan, John; Matty, Chris

2010-01-01

The Major Constituent Analyzer is a mass spectrometer based system that measures the major atmospheric constituents on the International Space Station. A number of limited-life components require periodic changeout, including the analyzer (ORU 02) and the verification gas assembly (ORU 08). The longest lasting ORU 02 was recently replaced after a record service length of 1033 days. The comparatively high performance duration may be attributable to a reduced inlet flow rate into the analyzer, resulting in increased ion pump lifetime; however, there may be other factors as well. A recent schedule slip for delivery of replacement verification gas led to a demonstration that the calibration interval could be extended on a short-term basis. An analysis of ORU 08 performance characteristics indicates that it is possible to temporarily extend the calibration interval from 6 weeks to 12 weeks if necessary.

A Multistate Life Table Analysis of Union Regimes in the United States: Trends and Racial Differentials, 1970–2002

PubMed Central

Morgan, S. Philip; Wang, Zhenglian; Gu, Danan; Yang, Chingli

2013-01-01

We estimate trends and racial differentials in marriage, cohabitation, union formation and dissolution (union regimes) for the period 1970–2002 in the United States. These estimates are based on an innovative application of multistate life table analysis to pooled survey data. Our analysis demonstrates (1) a dramatic increase in the lifetime proportions of transitions from never-married, divorced or widowed to cohabiting; (2) a substantial decrease in the stability of cohabiting unions; (3) a dramatic increase in mean ages at cohabiting after divorce and widowhood; (4) a substantial decrease in direct transition from never-married to married; (5) a significant decrease in the overall lifetime proportion of ever marrying and re-marrying in the 1970s to 1980s but a relatively stable pattern in the 1990s to 2000–2002; and (6) a substantial decrease in the lifetime proportion of transition from cohabiting to marriage. We also present, for the first time, comparable evidence on differentials in union regimes between four racial groups. PMID:24179311

Qualification and Selection of Flight Diode Lasers for Space Applications

NASA Technical Reports Server (NTRS)

Liebe, Carl C.; Dillon, Robert P.; Gontijo, Ivair; Forouhar, Siamak; Shapiro, Andrew A.; Cooper, Mark S.; Meras, Patrick L.

2010-01-01

The reliability and lifetime of laser diodes is critical to space missions. The Nuclear Spectroscopic Telescope Array (NuSTAR) mission includes a metrology system that is based upon laser diodes. An operational test facility has been developed to qualify and select, by mission standards, laser diodes that will survive the intended space environment and mission lifetime. The facility is situated in an electrostatic discharge (ESD) certified clean-room and consist of an enclosed temperature-controlled stage that can accommodate up to 20 laser diodes. The facility is designed to characterize a single laser diode, in addition to conducting laser lifetime testing on up to 20 laser diodes simultaneously. A standard laser current driver is used to drive a single laser diode. Laser diode current, voltage, power, and wavelength are measured for each laser diode, and a method of selecting the most adequate laser diodes for space deployment is implemented. The method consists of creating histograms of laser threshold currents, powers at a designated current, and wavelengths at designated power. From these histograms, the laser diodes that illustrate a performance that is outside the normal are rejected and the remaining lasers are considered spaceborne candidates. To perform laser lifetime testing, the facility is equipped with 20 custom laser drivers that were designed and built by California Institute of Technology specifically to drive NuSTAR metrology lasers. The laser drivers can be operated in constant-current mode or alternating-current mode. Situated inside the enclosure, in front of the laser diodes, are 20 power-meter heads to record laser power throughout the duration of lifetime testing. Prior to connecting a laser diode to the current source for characterization and lifetime testing, a background program is initiated to collect current, voltage, and resistance. This backstage data collection enables the operational test facility to have full laser diode traceablity.

Lifetime predictions for the Solar Maximum Mission (SMM) and San Marco spacecraft

NASA Technical Reports Server (NTRS)

Smith, E. A.; Ward, D. T.; Schmitt, M. W.; Phenneger, M. C.; Vaughn, F. J.; Lupisella, M. L.

1989-01-01

Lifetime prediction techniques developed by the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) are described. These techniques were developed to predict the Solar Maximum Mission (SMM) spacecraft orbit, which is decaying due to atmospheric drag, with reentry predicted to occur before the end of 1989. Lifetime predictions were also performed for the Long Duration Exposure Facility (LDEF), which was deployed on the 1984 SMM repair mission and is scheduled for retrieval on another Space Transportation System (STS) mission later this year. Concepts used in the lifetime predictions were tested on the San Marco spacecraft, which reentered the Earth's atmosphere on December 6, 1988. Ephemerides predicting the orbit evolution of the San Marco spacecraft until reentry were generated over the final 90 days of the mission when the altitude was less than 380 kilometers. The errors in the predicted ephemerides are due to errors in the prediction of atmospheric density variations over the lifetime of the satellite. To model the time dependence of the atmospheric densities, predictions of the solar flux at the 10.7-centimeter wavelength were used in conjunction with Harris-Priester (HP) atmospheric density tables. Orbital state vectors, together with the spacecraft mass and area, are used as input to the Goddard Trajectory Determination System (GTDS). Propagations proceed in monthly segments, with the nominal atmospheric drag model scaled for each month according to the predicted monthly average value of F10.7. Calibration propagations are performed over a period of known orbital decay to obtain the effective ballistic coefficient. Progagations using plus or minus 2 sigma solar flux predictions are also generated to estimate the despersion in expected reentry dates. Definitive orbits are compared with these predictions as time expases. As updated vectors are received, these are also propagated to reentryto continually update the lifetime predictions.

Determination of biological activity from fluorescence-lifetime measurements in Saccharomyces cerevisiae

NASA Astrophysics Data System (ADS)

Rudek, F.; Baselt, T.; Lempe, B.; Taudt, C.; Hartmann, P.

2015-03-01

The importance of fluorescence lifetime measurement as an optical analysis tool is growing. Many applications already exist in order to determine the fluorescence lifetime, but the majority of these require the addition of fluorescence-active substances to enable measurements. Every usage of such foreign materials has an associated risk. This paper investigates the use of auto-fluorescing substances in Saccharomyces cerevisiae (Baker's yeast) as a risk free alternative to fluorescence-active substance enabled measurements. The experimental setup uses a nitrogen laser with a pulse length of 350 ps and a wavelength of 337 nm. The excited sample emits light due to fluorescence of NADH/NADPH and collagen. A fast photodiode collects the light at the output of an appropriate high-pass edge-filter at 400 nm. Fluorescence lifetimes can be determined from the decay of the measurement signals, which in turn characterizes the individual materials and their surrounding environment. Information about the quantity of the fluorescence active substances can also be measured based on the received signal intensity. The correlation between the fluorescence lifetime and the metabolic state of Saccharomyces cerevisiae was investigated and is presented here.

Effects of substrate voltage on noise characteristics and hole lifetime in SOI metal-oxide-semiconductor field-effect transistor photon detector.

PubMed

Putranto, Dedy Septono Catur; Priambodo, Purnomo Sidi; Hartanto, Djoko; Du, Wei; Satoh, Hiroaki; Ono, Atsushi; Inokawa, Hiroshi

2014-09-08

Low-frequency noise and hole lifetime in silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) are analyzed, considering their use in photon detection based on single-hole counting. The noise becomes minimum at around the transition point between front- and back-channel operations when the substrate voltage is varied, and increases largely on both negative and positive sides of the substrate voltage showing peculiar Lorentzian (generation-recombination) noise spectra. Hole lifetime is evaluated by the analysis of drain current histogram at different substrate voltages. It is found that the peaks in the histogram corresponding to the larger number of stored holes become higher as the substrate bias becomes larger. This can be attributed to the prolonged lifetime caused by the higher electric field inside the body of SOI MOSFET. It can be concluded that, once the inversion channel is induced for detection of the photo-generated holes, the small absolute substrate bias is favorable for short lifetime and low noise, leading to high-speed operation.

Distinguishability of stacks in ZnTe/ZnSe quantum dots via spectral analysis of Aharonov-Bohm oscillations

NASA Astrophysics Data System (ADS)

Roy, Bidisha; Ji, Haojie; Dhomkar, Siddharth; Cadieu, Fred J.; Peng, Le; Moug, Richard; Tamargo, Maria C.; Kuskovsky, Igor L.

2013-02-01

A spectral analysis of the Aharonov-Bohm (AB) oscillations in photoluminescence intensity was performed for stacked type-II ZnTe/ZnSe quantum dots (QDs) fabricated within multilayered Zn-Se-Te system with sub-monolayer insertions of Te. Robust AB oscillations allowed for fine probing of distinguishable QDs stacks within the ensemble of QDs. The AB transition magnetic field, B AB , changed from the lower energy side to the higher energy side of the PL spectra revealing the presence of different sets of QDs stacks. The change occurs within the spectral range, where the contributing green and blue bands of the spectra overlapped. "Bundling" in lifetime measurements is seen at transition spectral regions confirming the results.

CRRES microelectronics package flight data analysis

NASA Technical Reports Server (NTRS)

Stassinopoulos, E. G.; Brucker, G. J.; Stauffer, C. A.

1993-01-01

A detailed in-depth analysis was performed on the data from some of the CRRES MEP (Microelectronics Package) devices. These space flight measurements covered a period of about fourteen months of mission lifetime. Several types of invalid data were identified and corrections were made. Other problems were noted and adjustments applied, as necessary. Particularly important and surprising were observations of abnormal device behavior in many parts that could neither be explained nor correlated to causative events. Also, contrary to prevailing theory, proton effects appeared to be far more significant and numerous than cosmic ray effects. Another unexpected result was the realization that only nine out of thirty-two p-MOS dosimeters on the MEP indicated a valid operation. Comments, conclusions, and recommendations are given.

[Quenched fluorescein: a reference dye for instrument response function of TCSPC].

PubMed

Pan, Hai-feng; Ding, Jing-xin; Liang, Rong-rong; Tao, Zhan-dong; Liu, Meng-wei; Zhang, San-jun; Xu, Jian-hua

2014-08-01

Measuring the instrument response function (IRF) and fitting by reconvolution algorithms are routines to improve time resolution in fluorescence lifetime measurements. Iodide ions were successfully used to quench the fluorescence of fluorescein in this study. By systematically adding saturated NaI water solution in basic fluorescein solution, the lifetimes of fluorescein were reduced from 4 ns to 24 ps. The quenched lifetime of fluorescein obtained from the analysis of Time-Correlated Single Photon Counting (TCSPC) measurement agrees well with that from femtosecond frequency up-conversion measurement. In time resolved excitation spectra measurements, the IRF should be measured at various detection wavelengths providing scattring materials are used. This study could not only reduce the complexity of IRF measurement, but also avoid the existing color effect in system. This study should have wide applications in time resolved fluorescence spectroscopy and fluorescence lifetime imaging.

Studies for Io's extended atmosphere and neutral clouds and their impact on the local satellite atmosphere and on the planetary magnetosphere

NASA Technical Reports Server (NTRS)

Smyth, William H.

1993-01-01

The research performed in this project is divided in two main investigations: (1) the synthesis and analysis of a collection of independent observations for Io's sodium corona, its sodium extended atmosphere, and the sodium cloud, and (2) the analysis of a (System III longitude correlated) space-time 'bite-out' near western elongation in the 1981 sodium cloud images from the JPL Table Mountain Sodium Cloud Data Set. For the first investigation, modeling analysis of the collective observed spatial profiles has shown that they are reproduced by adopting at Io's exobase a modified sputtering flux speed distribution function which is peaked near 0.5 km/s and has a small high-speed (15-20 km/s) nonisotropic component. The nonisotropic high-speed component is consistent with earlier modeling of the trailing directional feature. For the second investigation, modeling analysis of the 'bite-out' observed near western elongation (but not eastern elongation) has shown that it is reproduced in model calculation by adopting a plasma torus description for the sodium lifetime that is inherently asymmetric in System III longitudes of the active sector and that also has an east-west asymmetry. The east-west and System III longitude asymmetries were determined from independent observations for the plasma torus in 1981. The presence of the 'bite-out' feature only near western elongation may be understood in terms of the relative value for sodium of its lifetime and its transport time through the System III enhanced plasma torus region.

Current Research in Aircraft Tire Design and Performance

NASA Technical Reports Server (NTRS)

Tanner, J. A.; Mccarthy, J. L.; Clark, S. K.

1981-01-01

A review of the tire research programs which address the various needs identified by landing gear designers and airplane users is presented. The experimental programs are designed to increase tire tread lifetimes, relate static and dynamic tire properties, establish the tire hydroplaning spin up speed, study gear response to tire failures, and define tire temperature profiles during taxi, braking, and cornering operations. The analytical programs are aimed at providing insights into the mechanisms of heat generation in rolling tires and developing the tools necessary to streamline the tire design process and to aid in the analysis of landing gear problems.

A Consumer-Oriented Control Framework for Performance Analysis in Hybrid Electric Vehicles

DOE PAGES

Shaltout, Mohamed L.; Malikopoulos, Andreas A.; Pannala, Sreekanth; ...

2014-12-09

Hybrid electric vehicles (HEVs) have attracted considerable attention due to their potential to reduce fuel consumption and emissions. Our objective with this paper is to enhance our understanding of the associated tradeoffs among the HEV subsystems, e.g., the engine, the motor, and the battery, and investigate the related implications for fuel consumption and battery capacity and lifetime. Addressing this problem can provide insights on how to prioritize these objectives based on consumers needs and preferences. The results of the proposed optimization approach can also be used to investigate the implications for HEV costs related to ownership and warranty.

Exploring a nonminimal sterile neutrino model involving decay at IceCube

NASA Astrophysics Data System (ADS)

Moss, Z.; Moulai, M. H.; Argüelles, C. A.; Conrad, J. M.

2018-03-01

We study the phenomenology of neutrino decay together with neutrino oscillations in the context of eV-scale sterile neutrinos. We review the formalism of visible neutrino decay in which one of the decay products is a neutrino that potentially can be observed. We apply the formalism developed for decay to the recent sterile neutrino search performed by IceCube with TeV neutrinos. We show that for a ν4 lifetime τ4/m4≲10-16 eV-1 s , the interpretation of the high-energy IceCube analysis can be significantly changed.

Er3+-doped BaY2F8 crystal waveguides for broadband optical amplification at 1.5 μm

NASA Astrophysics Data System (ADS)

Toccafondo, V.; Cerqueira S., A.; Faralli, S.; Sani, E.; Toncelli, A.; Tonelli, M.; Di Pasquale, F.

2007-01-01

Integrated waveguide amplifiers based on high concentration Er3+ doped BaY2F8 crystals are numerically studied by combining a full-vectorial finite element based modal analysis and propagation-rate equations. Using realistic input data, such as the absorption/emission cross sections and Er level lifetimes measured on grown crystal samples, we investigate the amplifier performance by optimizing the total Er concentration. We predict optimum gain coefficient up to 5dB/cm and broad amplification bandwidth exceeding 80nm with 1480nm pumping.

Development of a lifetime prediction model for lithium-ion batteries based on extended accelerated aging test data

NASA Astrophysics Data System (ADS)

Ecker, Madeleine; Gerschler, Jochen B.; Vogel, Jan; Käbitz, Stefan; Hust, Friedrich; Dechent, Philipp; Sauer, Dirk Uwe

2012-10-01

Battery lifetime prognosis is a key requirement for successful market introduction of electric and hybrid vehicles. This work aims at the development of a lifetime prediction approach based on an aging model for lithium-ion batteries. A multivariable analysis of a detailed series of accelerated lifetime experiments representing typical operating conditions in hybrid electric vehicle is presented. The impact of temperature and state of charge on impedance rise and capacity loss is quantified. The investigations are based on a high-power NMC/graphite lithium-ion battery with good cycle lifetime. The resulting mathematical functions are physically motivated by the occurring aging effects and are used for the parameterization of a semi-empirical aging model. An impedance-based electric-thermal model is coupled to the aging model to simulate the dynamic interaction between aging of the battery and the thermal as well as electric behavior. Based on these models different drive cycles and management strategies can be analyzed with regard to their impact on lifetime. It is an important tool for vehicle designers and for the implementation of business models. A key contribution of the paper is the parameterization of the aging model by experimental data, while aging simulation in the literature usually lacks a robust empirical foundation.

Lifetime and 12-Month Nonsuicidal Self-Injury and Academic Performance in College Freshmen.

PubMed

Kiekens, Glenn; Claes, Laurence; Demyttenaere, Koen; Auerbach, Randy P; Green, Jennifer G; Kessler, Ronald C; Mortier, Philippe; Nock, Matthew K; Bruffaerts, Ronny

2016-10-01

We examined whether nonsuicidal self-injury (NSSI) is associated with academic performance in college freshmen, using census-based web surveys (N = 7,527; response = 65.4%). NSSI was assessed with items from the Self-Injurious Thoughts and Behaviors Interview and subsequently linked with the administratively recorded academic year percentage (AYP). Freshmen with lifetime and 12-month NSSI showed a reduction in AYP of 3.4% and 5.9%, respectively. The college environment was found to moderate the effect of 12-month NSSI, with more strongly reduced AYPs in departments with higher-than-average mean departmental AYPs. The findings suggest that overall stress and test anxiety are underlying processes between NSSI membership and academic performance. © 2016 The American Association of Suicidology.

Health Risk Factors Associated with Lifetime Abstinence from Alcohol in the 1979 National Longitudinal Survey of Youth Cohort.

PubMed

Kerr, William C; Lui, Camillia K; Williams, Edwina; Ye, Yu; Greenfield, Thomas K; Lown, E Anne

2017-02-01

The choice and definition of a comparison group in alcohol-related health studies remains a prominent issue in alcohol epidemiology due to potential biases in the risk estimates. The most commonly used comparison group has been current abstainers; however, this includes former drinkers who may have quit drinking due to health problems. Lifetime abstention could be the best option, but measurement issues, selection biases due to health and other risk factors, and small numbers in populations are important concerns. This study examines characteristics of lifetime abstention and occasional drinking that are relevant for alcohol-related health studies. This study used data from the National Longitudinal Survey of Youth 1979 cohort of 14 to 21 year olds followed through 2012 (n = 7,515). Definitions of abstinence and occasional drinking were constructed based on multiple measurements. Descriptive analyses were used to compare the definitions, and in further analysis, lifetime abstainers (n = 718) and lifetime minimal drinkers (n = 1,027) were compared with drinkers across demographics and early-life characteristics (i.e., religion, poverty, parental education, and family alcohol problems) in logistic regression models. Using a strict measurement of zero drinks from adolescence to the 50s, only 1.7% of the sample was defined as lifetime abstainer compared to a broader definition allowing a total of 1 drink over the lifetime that included 9.5% and to lifetime minimal drinking (a total of 3 drinks or less a month), which accounted for 13.7%. Factors significantly associated with lifetime abstention and lifetime minimal drinking included religion, poverty, having no family alcohol problems, Hispanic ethnicity, foreign-born, and female gender. Importantly, work-related health limitations in early life were significantly associated, but not childhood physical and mental health problems. Alcohol-related health studies should utilize lifetime classifications of drinkers and abstainers, and, in doing so, should account for early-life socioeconomic adversity and childhood health factors or consider these as unmeasured confounders. Copyright © 2017 by the Research Society on Alcoholism.

Spectral analysis of fundus autofluorescence pattern as a tool to detect early stages of degeneration in the retina and retinal pigment epithelium.

PubMed

Feldman, Tatiana B; Yakovleva, Marina A; Larichev, Andrey V; Arbukhanova, Patimat M; Radchenko, Alexandra Sh; Borzenok, Sergey A; Kuzmin, Vladimir A; Ostrovsky, Mikhail A

2018-05-22

The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium (RPE). RPE cell suspension samples were obtained from the cadaver eyes with and without signs of age-related macular degeneration (AMD). Fluorescence analysis at an excitation wavelength of 488 nm was performed. The fluorescence lifetimes of lipofuscin-granule fluorophores were measured by counting time-correlated photon method. Comparative analysis of fluorescence spectra of RPE cell suspensions from the cadaver eyes with and without signs of AMD showed a significant difference in fluorescence intensity at 530-580 nm in response to fluorescence excitation at 488 nm. It was notably higher in eyes with visual pathology than in normal eyes regardless of the age of the eye donor. Measurements of fluorescence lifetimes of lipofuscin fluorophores showed that the contribution of photooxidation and photodegradation products of bisretinoids to the total fluorescence at 530-580 nm of RPE cell suspensions was greater in eyes with visual pathology than in normal eyes. Because photooxidation and photodegradation products of bisretinoids are markers of photodestructive processes, which can cause RPE cell death and initiate degenerative processes in the retina, quantitative determination of increases in these bisretinoid products in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and RPE.

Damage tolerance certification of a fighter horizontal stabilizer

NASA Astrophysics Data System (ADS)

Huang, Jia-Yen; Tsai, Ming-Yang; Chen, Jong-Sheng; Ong, Ching-Long

1995-05-01

A review of the program for the damage tolerance certification test of a composite horizontal stabilizer (HS) of a fighter is presented. The object of this program is to certify that the fatigue life and damage tolerance strength of a damaged composite horizontal stabilizer meets the design requirements. According to the specification for damage tolerance certification, a test article should be subjected to two design lifetimes of flight-by-flight load spectra simulating the in-service fatigue loading condition for the aircraft. However, considering the effect of environmental change on the composite structure, one additional lifetime test was performed. In addition, to evaluate the possibilities for extending the service life of the structure, one more lifetime test was carried out with the spectrum increased by a factor of 1.4. To assess the feasibility and reliability of repair technology on a composite structure, two damaged areas were repaired after two lifetimes of damage tolerance test. On completion of four lifetimes of the damage tolerance test, the static residual strength was measured to check whether structural strength after repair met the requirements. Stiffness and static strength of the composite HS with and without damage were evaluated and compared.

Minority carrier lifetimes in very long-wave infrared InAs/GaInSb superlattices

DOE PAGES

Olson, Benjamin Varberg; Haugan, Heather J.; Brown, Gail J.; ...

2016-01-01

Here, significantly improved carrier lifetimes in very-long wave infrared InAs/GaInSb superlattice(SL) absorbers are demonstrated by using time-resolved microwave reflectance (TMR) measurements. A nominal 47.0 Å InAs/21.5 Å Ga 0.75In 0.25Sb SLstructure that produces an approximately 25 μm response at 10 K has a minority carrier lifetime of 140 ± 20 ns at 18 K, which is markedly long for SL absorber with such a narrow bandgap. This improvement is attributed to the strain-engineered ternary design. Such SL employs a shorter period with reduced gallium in order to achieve good optical absorption and epitaxial advantages, which ultimately leads to the improvementsmore » in the minority carrier lifetime by reducing Shockley–Read–Hall (SRH) defects. By analyzing the temperature-dependence of TMR decay data, the recombination mechanisms and trap states that currently limit the performance of this SL absorber have been identified. The results show a general decrease in the long-decay lifetime component, which is dominated by the SRH recombination at temperature below ~30 K, and by Auger recombination at temperatures above ~45 K.« less

A Temperature-Dependent Battery Model for Wireless Sensor Networks.

PubMed

Rodrigues, Leonardo M; Montez, Carlos; Moraes, Ricardo; Portugal, Paulo; Vasques, Francisco

2017-02-22

Energy consumption is a major issue in Wireless Sensor Networks (WSNs), as nodes are powered by chemical batteries with an upper bounded lifetime. Estimating the lifetime of batteries is a difficult task, as it depends on several factors, such as operating temperatures and discharge rates. Analytical battery models can be used for estimating both the battery lifetime and the voltage behavior over time. Still, available models usually do not consider the impact of operating temperatures on the battery behavior. The target of this work is to extend the widely-used Kinetic Battery Model (KiBaM) to include the effect of temperature on the battery behavior. The proposed Temperature-Dependent KiBaM (T-KiBaM) is able to handle operating temperatures, providing better estimates for the battery lifetime and voltage behavior. The performed experimental validation shows that T-KiBaM achieves an average accuracy error smaller than 0.33%, when estimating the lifetime of Ni-MH batteries for different temperature conditions. In addition, T-KiBaM significantly improves the original KiBaM voltage model. The proposed model can be easily adapted to handle other battery technologies, enabling the consideration of different WSN deployments.

A Temperature-Dependent Battery Model for Wireless Sensor Networks

PubMed Central

Rodrigues, Leonardo M.; Montez, Carlos; Moraes, Ricardo; Portugal, Paulo; Vasques, Francisco

2017-01-01

Energy consumption is a major issue in Wireless Sensor Networks (WSNs), as nodes are powered by chemical batteries with an upper bounded lifetime. Estimating the lifetime of batteries is a difficult task, as it depends on several factors, such as operating temperatures and discharge rates. Analytical battery models can be used for estimating both the battery lifetime and the voltage behavior over time. Still, available models usually do not consider the impact of operating temperatures on the battery behavior. The target of this work is to extend the widely-used Kinetic Battery Model (KiBaM) to include the effect of temperature on the battery behavior. The proposed Temperature-Dependent KiBaM (T-KiBaM) is able to handle operating temperatures, providing better estimates for the battery lifetime and voltage behavior. The performed experimental validation shows that T-KiBaM achieves an average accuracy error smaller than 0.33%, when estimating the lifetime of Ni-MH batteries for different temperature conditions. In addition, T-KiBaM significantly improves the original KiBaM voltage model. The proposed model can be easily adapted to handle other battery technologies, enabling the consideration of different WSN deployments. PMID:28241444

Multispectral analog-mean-delay fluorescence lifetime imaging combined with optical coherence tomography

PubMed Central

Nam, Hyeong Soo; Kang, Woo Jae; Lee, Min Woo; Song, Joon Woo; Kim, Jin Won; Oh, Wang-Yuhl; Yoo, Hongki

2018-01-01

The pathophysiological progression of chronic diseases, including atherosclerosis and cancer, is closely related to compositional changes in biological tissues containing endogenous fluorophores such as collagen, elastin, and NADH, which exhibit strong autofluorescence under ultraviolet excitation. Fluorescence lifetime imaging (FLIm) provides robust detection of the compositional changes by measuring fluorescence lifetime, which is an inherent property of a fluorophore. In this paper, we present a dual-modality system combining a multispectral analog-mean-delay (AMD) FLIm and a high-speed swept-source optical coherence tomography (OCT) to simultaneously visualize the cross-sectional morphology and biochemical compositional information of a biological tissue. Experiments using standard fluorescent solutions showed that the fluorescence lifetime could be measured with a precision of less than 40 psec using the multispectral AMD-FLIm without averaging. In addition, we performed ex vivo imaging on rabbit iliac normal-looking and atherosclerotic specimens to demonstrate the feasibility of the combined FLIm-OCT system for atherosclerosis imaging. We expect that the combined FLIm-OCT will be a promising next-generation imaging technique for diagnosing atherosclerosis and cancer due to the advantages of the proposed label-free high-precision multispectral lifetime measurement. PMID:29675330

New approaches to the analysis of complex samples using fluorescence lifetime techniques and organized media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hertz, P.R.

Fluorescence spectroscopy is a highly sensitive and selective tool for the analysis of complex systems. In order to investigate the efficacy of several steady state and dynamic techniques for the analysis of complex systems, this work focuses on two types of complex, multicomponent samples: petrolatums and coal liquids. It is shown in these studies dynamic, fluorescence lifetime-based measurements provide enhanced discrimination between complex petrolatum samples. Additionally, improved quantitative analysis of multicomponent systems is demonstrated via incorporation of organized media in coal liquid samples. This research provides the first systematic studies of (1) multifrequency phase-resolved fluorescence spectroscopy for dynamic fluorescence spectralmore » fingerprinting of complex samples, and (2) the incorporation of bile salt micellar media to improve accuracy and sensitivity for characterization of complex systems. In the petroleum studies, phase-resolved fluorescence spectroscopy is used to combine spectral and lifetime information through the measurement of phase-resolved fluorescence intensity. The intensity is collected as a function of excitation and emission wavelengths, angular modulation frequency, and detector phase angle. This multidimensional information enhances the ability to distinguish between complex samples with similar spectral characteristics. Examination of the eigenvalues and eigenvectors from factor analysis of phase-resolved and steady state excitation-emission matrices, using chemometric methods of data analysis, confirms that phase-resolved fluorescence techniques offer improved discrimination between complex samples as compared with conventional steady state methods.« less

High-temperature dynamic behavior in bulk liquid water: A molecular dynamics simulation study using the OPC and TIP4P-Ew potentials

NASA Astrophysics Data System (ADS)

Gabrieli, Andrea; Sant, Marco; Izadi, Saeed; Shabane, Parviz Seifpanahi; Onufriev, Alexey V.; Suffritti, Giuseppe B.

2018-02-01

Classical molecular dynamics simulations were performed to study the high-temperature (above 300 K) dynamic behavior of bulk water, specifically the behavior of the diffusion coefficient, hydrogen bond, and nearest-neighbor lifetimes. Two water potentials were compared: the recently proposed "globally optimal" point charge (OPC) model and the well-known TIP4P-Ew model. By considering the Arrhenius plots of the computed inverse diffusion coefficient and rotational relaxation constants, a crossover from Vogel-Fulcher-Tammann behavior to a linear trend with increasing temperature was detected at T* ≈ 309 and T* ≈ 285 K for the OPC and TIP4P-Ew models, respectively. Experimentally, the crossover point was previously observed at T* ± 315-5 K. We also verified that for the coefficient of thermal expansion α P ( T, P), the isobaric α P ( T) curves cross at about the same T* as in the experiment. The lifetimes of water hydrogen bonds and of the nearest neighbors were evaluated and were found to cross near T*, where the lifetimes are about 1 ps. For T < T*, hydrogen bonds persist longer than nearest neighbors, suggesting that the hydrogen bonding network dominates the water structure at T < T*, whereas for T > T*, water behaves more like a simple liquid. The fact that T* falls within the biologically relevant temperature range is a strong motivation for further analysis of the phenomenon and its possible consequences for biomolecular systems.

Cognition and aging in a complex work environment: relationships with performance among air traffic control specialists.

PubMed

Becker, J T; Milke, R M

1998-10-01

Chronological age affects the performance of demanding cognitive tasks within the aviation environment. Within the domain of air traffic control (ATC), the ability to handle simultaneous visual and auditory input, or to return to a task after a break to complete another task, is critical to success and is the sort of cognitive function most affected by age. The limited available data suggest a strong relationship between age and job performance among ATC specialists, whether measured at the time of entry into the system or during the working lifetime of a full-performance-level controller. An analysis of the distribution of the ages of controllers currently in the system, and a projection for the years 2001 and 2006, leads to the conclusion that a high proportion of the ATC work force will be at risk for displaying age-related changes in job performance efficiency over the next 10 yr. It seems important, therefore, to determine the nature and extent of the age-related cognitive changes that can occur during the lifespan of a controller (i.e., 25-55 yr of age) and how these changes may affect job performance. The results of such an analysis should aid in the design and implementation of new control systems to minimize any deleterious effects of aging on performance.